Attachment Previews Stop Working After Upgrading Confluence
Platform Notice: Data Center Only - This article only applies to Atlassian products on the Data Center platform.
Note that this KB was created for the Data Center version of the product. Data Center KBs for non-Data-Center-specific features may also work for Server versions of the product, however they have not been tested. Support for Server* products ended on February 15th 2024. If you are running a Server product, you can visit the Atlassian Server end of support announcement to review your migration options.
*Except Fisheye and Crucible
Summary
After upgrading Confluence, attachment thumbnails may stop working.
Environment
7.4.7
Diagnosis
An error like this will appear in the logs:
1
2
2021-03-11 16:26:06,730 WARN [http-nio-8090-exec-15 url:/confluence/res...vertHD/185993966/1 username:xxxxxxxx] [plugins.conversion.impl.FileSystemConversionState] markAsError Creating error file: /data/confluence/dcl-document_hd/214/243/185993964/185993966_1.err
-- referer: Cause
Confluence uses a file format similar to the one described in our Hierarchical File System Attachment Storage kb article to store attachment thumbnails in the dcl-thumbnail directory. Specifically, we use this format:
dcl-thumbnail/<last 3 digits of page id % 250>/<next to last 3 digits of page id % 250>/<full page id>/<attachmentid>_<version>
So in this example the page id for this thumbnail:
dcl-thumbnail/160/243/185993660/185993714_1.err
would be 185993660 and the attachment id would be 185993714.
Once a .err extension is added to the end of the file, the thumbnail will no longer appear in the UI.
Solution
You can simply delete the .err file and then refresh the page, and Confluence will create a new thumbnail file and the thumbnail should show up in the UI again. You can also run these commands:
1
2
find . -name "*.err" -type f
find . -name "*.err" -type f -deletefrom the dcl-thumbnail directory to delete the .err files in bulk. The first one should give you a dry run of the files to be deleted, and the second would delete them.
Was this helpful?