All existing file attachments for a particular space are showing:
Attachment File Not Found
The attachment you were trying to download could not be found in the attachment file store. Either the file has been deleted manually or there was an error in removing the record of the attachment from Confluence.
If this attachment is no longer required you can delete it from Confluence on the attachments page. Otherwise, you will need to attach a new copy.
We have have confirmed the files still exist on the physical file system. Additionally any new file attachments work normally.
Some of the files do not appear to follow the hierarchy as specified in: https://confluence.atlassian.com/doc/hierarchical-file-system-attachment-storage-704578486.html
We are currently running Confluence Server 6.3.3
How do we go about restoring the file attachments? We have tried rebuilding the ancestors table and the content index.