No thumbnail for documents in the appliance


Steps to reproduce

  1. Open any document’s detail view
  2. Click on “versions”

Expected behaviour

A preview of the document, at least a generic icon

Actual behaviour

My brower’s version of “image not found”.

Server configuration

Operating system: UCS 4.3-2

Web server: Apache 2.4

Database: MySQL

PHP version: The one provided by the app

ownCloud version: 10.0.9

Updated from an older ownCloud or fresh install: Updated

Where did you install ownCloud from: Univention App Center

Signing status (ownCloud 9.0 and above):

List of activated apps: Activities, LDAP-Integration, Marketplace, Collabora



the latest ownCloud 10.0.10 release has the following in its Changelog :

Fix version previews to fall back to icon when no preview provider is available - #32474


Yeah, but this is the appliance. This user would have to wait until ownCloud releases the app for the appliance with the 10.0.10 version.

Manual user upgrades are not supported in the appliance.


Hey @tom42,

you write

What would be a preview provider? Can collabora act as one? Are there possible missing dependencies in the docker container from the AppCenter version?



Hey @dmitry,

we’re not using the appliance but installed ownCloud from the AppCenter, which, in the end, should be same.



Yes. As long you are using UCS - you are using the ownCloud app.

For this app there is no 10.0.10 version yet available.


UCS it is :slight_smile:



unfortunately i can’t answer any of these questions as i don’t have any knowledge about that. Just have seen the changelog entry while reading the changelog before updating my own ownCloud installation.

But i guess this just means that no provider is available for this specific document you’re trying to preview. Maybe you can find some notes on this in the ownCloud documentation?


There is a fix, it’s in the coming app release.

Here is the PR from GitHub.



yes i had found this fix and linked it previously. But if i understand it correctly that this only fixes the shown image if no “Preview provider” (whatever this is?) is available.

But i think @denissen is probably more interesting in making such a “Preview provider” available within the appliance so that a preview is shown or am i wrong?


oh, sorry. I haven’t seen that you already posted that link.

I currently can not verify or disprove what happens in 10.0.10 after the fix with the thumbnails. As soon as I can - I will report back.



i did the following search: and found the following note box which could explain what such “Preview providers” are and why these are not available within the appliance:

Older versions of ownCloud also supported the preview generation of other file types such as PDF, SVG or various office documents. Due to security concerns those providers have been disabled by default and are considered unsupported. While those providers are still available, we discourage enabling them, and they are not documented.


Thank you @tom42 and @dmitry, we will wait for the app update then and checking out the fix :slight_smile:



i don’t think that the app update won’t solve your initial issue about missing previews / thumbnails for documents. From what i understand the appliance just doesn’t provide / have configured the required preview providers to show previews / thumbnails for documents.


Even if the update does not solve the problem of missing previews for files other than image files, at least we won’t see the “image not found”-image any longer :slight_smile:


The app update solved the problems - we now can see the generic icons :slight_smile: