How do I fix :Receiving HTTP 500 error when clicking on Issue Attachements

[Joshua White]

We upgraded to V7 about a month ago, and have come to realize that all of the links to our issue attachments have been broken.  Clicking on a link takes us to a JIRA HTTP 500 error page.   Inspecting the file system has shown that the attachments at least are not lost, as there are still folders with them all present.  We were unable to find any questions or documentaiton related to this issue.

Please provide the steps necessary to re-link the attachments to our issues.

[Nic Brough -Adaptavist- · Accepted solution]

Start by checking that admin -> attachments shows the correct path to the root of the attachments, and that permissions and ownership on the directory is correct.  Then, I'd try re-indexing (just a project at first to see if that helps).  If that does not help, then I'd start reading the logs for errors (might be worth a shot first, but the others might be a quicker initial check)

[Joshua White]

By checking the settings under admin -> attachments we determined that the recent install was using the default directory location which resulted in the attachment links being incorrect.

The thumbnails are still not blank/default images, and re-indexing did not fix that.  Any ideas on how to fix the thumbnails?

[Nic Brough -Adaptavist-]

Bother, my JIRA-foo got me most of the way and then let me down.  I don't know of any way to fix the thumbnails.  My best guess is to clear out the thumbnails directories in the cache/temp areas, but I'm really not sure.

[Phill Fox]

One thing to check is it only new attachments that are without thumbnails or all old attachments as well? 
If it is only new attachments it is possible that you are experiencing the issue described here https://confluence.atlassian.com/confkb/confluence-doesn-t-generate-thumbnails-154068.html which although this article is written for Confluence it can also apply for JIRA. 
Also check the permissions on the thumbnails directory to make sure that is also correct. 

[Phill Fox]

As an administrator go to <yourhost>/secure/admin/ViewAttachmentSettings.jspa and check that the directory listed here for attachments matches where you think it should be. Also check that allow attachments is set to ON.
If this all looks correct then your next steps are checking that the service which is running for JIRA has the correct permissions to access this folder.