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Attached images becoming 'Unknown Attachments'.


When I open certain pages with attached images in 'Edit' mode, I find that the images are replaced by 'Unknown Attachment' placeholder text even though they've been physically attached to the page.

The funny thing is that if I proceed to save the page, the images are permanently replaced by the 'Unknown Attachment' placeholder text in View mode. The only way to retrieve them in this case is to revert the page to its previous version, and reattach the images before saving the page.

What could be causing this?



2 answers

0 votes

Hello there! Great to have you in our community, @Sean_Braganza.

What I got from your description, is that page attachments in specific pages become the “Unknown Attachment”.

I have seen this issue a few times and there is a chance that you are being affected by the following bug:


We could try to turn collaborative editing off and on. After that, we could check if the issue is still present. Here is how to proceed.

  1. Click the Cog icon in the top right corner
  2. Select General Configuration
  3. Select Collaborative editing
  4. Click Change Mode
  5. Select Off
  6. Apply
  7. Click Change Mode again
  8. Select On
  9. Apply
  10. Check if the issue is still present

For further investigation, would it be possible for you to give us a little more information? Here is a concise list of questions to help us better understand this situation:

  1. Is this affecting other types of attachments
  2. Do the affected attachments have special characters in their names?
  3. When did you first face this issue?
  4. Which version of Confluence are you running?


Let us hear from you, Sean! Looking forward to your reply.

Thanks for your response, Diego.

Turning collaborative editing on and off seemed to have no effect on the issue whatsoever. Regarding your questions:

1. No, so far it only seems to be affecting images.

2. No special characters in the name. Initially we were of the impression that solely PNG images were being affected, but this doesn't seem to be the case.

3. The issue began many months ago, somewhere around April - May, after we upgraded Confluence from 5.x.x to 6.x.x. That was the time we started missing a few missing images but it wasn't very prominent.

Last week we updated Confluence to 7.0.1, following which we started facing issues with our local server. The machine's memory modules were replaced, and that's when we started noticing more and more 'unknown attachments'.

This makes me feel that the 'unknown attachments' issue is caused by a servers-de problem more than anything, but I wouldn't know how exactly.

4. As I said, version 7.0.1.


Thanks for keeping the thread alive, @seanbCry !

I will now try to address some of the answers you brought to the table. Let us begin.

 “Turning collaborative editing on and off seemed to have no effect on the issue whatsoever.”

Are you referring to already problematic images (missing images) or even newly added images (after the off-on procedure) are affected?


“3. The issue began many months ago, somewhere around April - May, after we upgraded Confluence from 5.x.x to 6.x.x. That was the time we started missing a few missing images but it wasn't very prominent.”

We could try to re-index your instance and check if the images are still missing. There are two types of re-indexing. One that does not require restarting the instance and a more “complete” one. Here is the documentation for both:


One important note is that rebuilding the index from scratch requires instance downtime. Also, while the re-index via the interface (no restart needed) does not require downtime, you and your users will experience a degraded performance as a result of the process being executed. So it is highly advisable to also schedule downtime for this procedure as well.

Let us hear from you, Sean!

Hi @Sean_Braganza - was your "unknown attachment" issue resolved by re-indexing?

We are currently facing the exact same issue (Server 7.2.0): images that were attached and displayed in pages become "unknown attachment" when opening the editor.

This seems to happen randomly: not all pages are affected and initially we wrote it off as a user error (we have just converted from another tool and thought we had overlooked a few pages in the process). 


Hi Dorte,

Unfortunately I haven't had the chance to try the re-indexing method yet, as the downtime is something that would have to be coordinated with out on-site IT department.

We are noticing the missing images become more and more common though.


Thanks for getting back to me so quickly!

We had suspected this could be related to Scroll Versions - do you use that app also?




No not really, I doubt it's a plugin issue since we maintain two Confluence instances; one of them barely uses any plugins, and that one still seems to show broken image attachments.



Thanks for taking the time to reply :-) 

We'll do some more digging to resolve the issue.


No problem.


Do leave a message here if you manage to get it sorted. :)




Well, reindex from scratch did NOT solve the issue.

Will let you know when/if we find the cause...


Okay, thanks for the update!



We have started to experience similar issue today. Self-hosted 7.2.0. Reindexing won't help. Any ideas before raising support request? 

Our issue is still unresolved. We have been working with Atlassian support and they have been most helpful.

After some research, we have just agreed that the most likely cause for our issue is that we have used the unsupported plugin (

But there is no way to confirm this and it is worrying if you guys have not been using the unsupported plugin.

We can fix each issue manually in the affected pages but it would be a hopeless task if it just keeps appearing for some other reason...

We don't use any unsupported plugins, and still getting this issue.

We're experiencing the same issue. Self hosted Confluence v7.4.0.

We also encounter this problem every then and now. I found that when I switch to edit mode and then "..." button on the lower right > Revert to last published version brings the images back.

Still, reason is unknown :/

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