Mattermost, Inc.

[SOLVED] Attachment links not found (404) after Slack import using advanced exporter tool

Summary

Unable to preview or download attachments after Slack import using slack-advanced-exporter tool.

Steps to reproduce

Running Mattermost build 3.6.2 on Ubuntu 16.04

  1. Created Slack export and used slack-advanced-exporter to add attachments - worked fine, no errors.
  2. Imported Slack export file using Mattermost CLI - got some warnings and some errors “Unable to decode image err=image: unknown format” (full log below)
  3. After import the attachments appear in posts, but when I click on them they don’t preview or download. The links are returning 404 errors. Here’s an example https request result: {“id”:“api.file.read_file.reading_local.app_error”,“message”:“Encountered an error reading from local server storage”,“detailed_error”:"",“request_id”:“1ciru537ubdxbqxkgqugwyhk9y”,“status_code”:404}

Any suggestions for troubleshooting?

Thanks!
-Eric

CLI Slack Import log:

ubuntu@ip-172-31-13-137:/opt/mattermost/bin$ sudo ./platform import slack enlivening-edge ~/export-with-attachments.zip
Running Slack Import. This may take a long time for large teams or teams with many messages.
[2017/03/12 06:23:58 UTC] [EROR] Error saving user. err=User.IsValid: model.user.is_valid.email.app_error, user_id=u5rtemkq4bgcukmocspjgu3fde
[2017/03/12 06:23:59 UTC] [EROR] Error saving user. err=User.IsValid: model.user.is_valid.email.app_error, user_id=sjwihu3uafg9uxtdxzqin4tkta
[2017/03/12 06:23:59 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:23:59 UTC] [WARN] Unsupported post type: message, file_mention
[2017/03/12 06:23:59 UTC] [WARN] Unsupported post type: message, file_mention
[2017/03/12 06:23:59 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:23:59 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:23:59 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:23:59 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:23:59 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:23:59 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:23:59 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:00 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:00 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:00 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:00 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:00 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:00 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:00 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:00 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:00 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:00 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:00 UTC] [WARN] Unsupported post type: message, file_mention
[2017/03/12 06:24:01 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:01 UTC] [WARN] Unsupported post type: message, channel_name
[2017/03/12 06:24:01 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:01 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:01 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:01 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:01 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:01 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:02 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:02 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:02 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:02 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:03 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:03 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:03 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:03 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:03 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:21 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:22 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:22 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:23 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:23 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:23 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:23 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:23 UTC] [WARN] Unsupported post type: message, channel_topic
[2017/03/12 06:24:23 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:23 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:23 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:23 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:23 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:23 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:23 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:24 UTC] [WARN] Unsupported post type: message, channel_name
[2017/03/12 06:24:24 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:24 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:24 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:25 UTC] [WARN] Unsupported post type: message, channel_name
[2017/03/12 06:24:25 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:25 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:26 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:26 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:26 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:26 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:26 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:26 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:27 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:27 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:27 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:27 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:27 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:27 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:27 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:29 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:29 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:29 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:29 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:29 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:30 UTC] [WARN] Unsupported post type: message, bot_add
[2017/03/12 06:24:30 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:31 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:24:31 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:24:31 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:31 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:31 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:24:32 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:24:32 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:12 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:14 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:15 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:15 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:18 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:19 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:19 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:19 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:19 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:20 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:20 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:31 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:31 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:31 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:31 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:31 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:32 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:32 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:35 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:35 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:35 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:36 UTC] [WARN] Unsupported post type: message, bot_add
[2017/03/12 06:26:36 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:36 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:36 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:37 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:37 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:37 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:37 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:38 UTC] [WARN] Unsupported post type: message, reply_broadcast
[2017/03/12 06:26:38 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:38 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:38 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:38 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:38 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:39 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:39 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:39 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:39 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:39 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:39 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:39 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:39 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:39 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:40 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:41 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:41 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:42 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:42 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:42 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:42 UTC] [WARN] Unsupported post type: message, reply_broadcast
[2017/03/12 06:26:42 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:43 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:43 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:43 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:43 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:43 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:46 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:46 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:46 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:46 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:46 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:46 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:47 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:47 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:47 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:48 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:48 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:48 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:48 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:49 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:49 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:49 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:49 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:49 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:49 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:49 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:49 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:49 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:49 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:49 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:49 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:49 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:49 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:50 UTC] [WARN] Unsupported post type: message, file_mention
[2017/03/12 06:26:51 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:51 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:51 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:53 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:53 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:53 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:53 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:54 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:54 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:54 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:54 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:55 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:55 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:55 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:55 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:55 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:56 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:56 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:56 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:57 UTC] [WARN] Unsupported post type: message, reply_broadcast
[2017/03/12 06:26:58 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:58 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:58 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:58 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:26:58 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:58 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:26:59 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:59 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:59 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:59 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:59 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:59 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:26:59 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:59 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:26:59 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:00 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:00 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:00 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:00 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:00 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:01 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:01 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:01 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:02 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:02 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:02 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:02 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:02 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:05 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:08 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:08 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:08 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:08 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:08 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:08 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:08 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:08 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:08 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:08 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:09 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:09 UTC] [WARN] Unsupported post type: message, bot_add
[2017/03/12 06:27:09 UTC] [WARN] Unsupported post type: message, bot_remove
[2017/03/12 06:27:09 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:09 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:09 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:09 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:09 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:09 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:09 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:10 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:10 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:10 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:10 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:10 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:10 UTC] [WARN] Unsupported post type: message, file_mention
[2017/03/12 06:27:10 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:10 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:10 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:10 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:10 UTC] [WARN] Unsupported post type: message, channel_name
[2017/03/12 06:27:10 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:10 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:11 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:13 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:13 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:13 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:13 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:13 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:13 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:13 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:14 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_name
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:14 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, file_mention
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_topic
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:14 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:14 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:15 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:15 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:15 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:15 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:15 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:15 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:16 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:16 UTC] [EROR] Unable to upload thumbnail path= err=WriteFile: api.file.write_file_locally.writing.app_error, open /opt/mattermost/data/: is a directory
[2017/03/12 06:27:16 UTC] [EROR] Unable to upload preview path= err=WriteFile: api.file.write_file_locally.writing.app_error, open /opt/mattermost/data/: is a directory
[2017/03/12 06:27:16 UTC] [WARN] Unsupported post type: message, slackbot_response
[2017/03/12 06:27:16 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:16 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:17 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:17 UTC] [WARN] Unsupported post type: message, bot_disable
[2017/03/12 06:27:17 UTC] [WARN] Unsupported post type: message, bot_disable
[2017/03/12 06:27:17 UTC] [WARN] Unsupported post type: message, reply_broadcast
[2017/03/12 06:27:18 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:18 UTC] [WARN] Unsupported post type: message, pinned_item
[2017/03/12 06:27:18 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:18 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:19 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:19 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:22 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:22 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:22 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:25 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:25 UTC] [EROR] Unable to decode image err=image: unknown format
[2017/03/12 06:27:25 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:25 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:26 UTC] [WARN] Unsupported post type: message, channel_archive
[2017/03/12 06:27:26 UTC] [WARN] Unsupported post type: message, channel_purpose
[2017/03/12 06:27:26 UTC] [WARN] Unsupported post type: message, channel_purpose
Finished Slack Import.

I should mention that the 404 errors are happening not just on image files (which might be explained by the errors in the import file), but also on other file types such as Word files.

Found the problem: the /opt/mattermost/data/team/ directory and all contents had owner:group set to root:root instead of mattermost:mattermost.

Thanks @ebabinet! Glad your issue is resolved :slight_smile:

Hi, I am somewhat new to the topic. Can you point me to a source explaining how to use the advanced exporter tool? I need to import a Slack team to a self-hosted MM server. :-/ Kind regards, /me.

Hi @meszi,

Thanks for your question,

You can read about Slack import here.