[Bug]: Virtual files thumbnails not working

[ParisGreen]

⚠️ Before submitting, please verify the following: ⚠️

• This is a bug, not a question or a configuration issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server and Desktop Client are up to date. See Server Maintenance and Release Schedule and Desktop Releases for supported versions.
• I agree to follow Nextcloud's Code of Conduct

Bug description

virtual files aren't showing thumbnails, even on files available locally

Steps to reproduce

Enable Virtual Files on windows

Expected behavior

Virtual files include thumbnails

Which files are affected by this bug

birdie.jpg

Operating system

Windows

Which version of the operating system you are running.

10

Package

Appimage

Nextcloud Server version

24.0.5.1

Nextcloud Desktop Client version

3.6.4

Is this bug present after an update or on a fresh install?

Fresh desktop client install

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

Are you using an external user-backend?

• Default internal user-backend
• LDAP/ Active Directory
• SSO - SAML
• Other

Nextcloud Server logs

No response

Additional info

I'm not sure if this is a bug or if I set something up wrong, but I'm not seeing previews for virtual files anymore, even if they're saved locally. I could swear this wasn't the case previously, and it's a bit inconvenient to boot.

[ParisGreen]

Just for reference, I tried reverting to client 3.5.2 and it behaves the way I'd expect with thumbnails. Hopefully that at least confirms it's a bug, and not user error.

[Moosetracks555]

If you copy a file that has a thumbnail into a nextcloud directory the thumbnail shows in the nextcloud directory until the file is synced. As soon as the file syncs the thumbnail goes to a white page. Has anyone found a work around for this?

[Leinad4Mind]

Any news? Same problem here. Very annoying.

[wonx]

I am also experiencing this bug.

[3dK]

Same here with Version 3.9.0 (Windows).
Image thumbnails not showing, but showing for video files.

[sachz19]

Hi, experiencing the same issue on multiple clients on the latest agent version.

[git-kick]

+1 would greatly appreciate to see that one solved.

[PW87]

I´ve the same problem. I´m using Version 3.10.0 (Windows - enable support for virtual files). When I open a folder with imagefiles, I can see all the thumbnails first. A few seconds later the thumbnails disappear one by one. I hope the issue could be fixed soon.

[PhilippSchlesinger]

I confirm the same problem as described above by the reporter and those who commented.
I may be able to provide you with a workaround and an approach to the issue below.

In search of the root of the problem, I tried other steps first:

• I removed the relevant sync folder in the Nextcloud client and added it again. This completely recreated the placeholder files.
  There was no change to the thumbnails issue.
• I cleared the thumbnail cache as described at https://www.tenforums.com/tutorials/5655-clear-reset-thumbnail-cache-windows-10-a.html.
  This also resulted in no change to the thumbnails
• I have reinstalled the latest release of the Nextcloud client under the user account in question.
  After the final necessary reboot and login, the thumbnails suddenly appeared, both for hydrated and for dehydrated files.
  But this is still not the answer to the problem.

Upon further testing I came to the following conclusion:

If there are multiple user accounts on the Windows system, thumbnails will be displayed in the account where the first login occurs. If there is a logout on the first user account, thumbnails will be displayed correctly after logging in again on the second account. If a second account is logged in parallel to the first, no thumbnails will be displayed there. If there is a logout on the first user account, thumbnails will be displayed correctly after logging out and in again on the second account.

[PhilippSchlesinger]

An additional note: It is sufficient to ensure that only one instance of Nextcloud is running at the same time on a Windows system.
Therefore, if you close the Nextcloud Client on a Windows account and then start the Nextcloud Client on a different account, the display of thumbnails will work there.
(I could reproduce the issue on at least different Windows systems)

@ParisGreen, @PW87, @git-kick, @sachz19, @3dK, @wonx and others who confirmed that bug: could you please test and report back if that is a workaround for you?

@allexzander, @mgallien Does the issue relate to the way in which the thumbnail provider shell extension registers itself with Windows Explorer?

[sachz19]

Hi, All systems I had the issue with only have a single user known on the system. No other users running in the background. Since updating it has fixed itself on my system, I still have to check the other systems to see if the issue is resolved after updating, due to holiday I haven’t had the time yet to check. Thanks for the thorough investigation! From: PhilippSchlesinger ***@***.***> Sent: donderdag 19 oktober 2023 12:29 To: nextcloud/desktop ***@***.***> Cc: sachz19 ***@***.***>; Mention ***@***.***> Subject: Re: [nextcloud/desktop] [Bug]: Virtual files thumbnails not working (Issue #5301) An additional note: It is sufficient to ensure that only one instance of Nextcloud is running at the same time on a Windows system. Therefore, if you close the Nextcloud Client on a Windows account and then start the Nextcloud Client on a different account, the display of thumbnails will work there. @ParisGreen <https://github.com/ParisGreen> , @PW87 <https://github.com/PW87> , @git-kick <https://github.com/git-kick> , @sachz19 <https://github.com/sachz19> , @3dK <https://github.com/3dK> , @wonx <https://github.com/wonx> and others who confirmed that bug: could you please test and report back if that is a workaround for you? @allexzander <https://github.com/allexzander> , @mgallien <https://github.com/mgallien> Does the issue relate to the way in which the thumbnail provider shell extension registers itself with Windows Explorer? — Reply to this email directly, view it on GitHub <#5301 (comment)> , or unsubscribe <https://github.com/notifications/unsubscribe-auth/AXLUW3BAARUNOJNVDPQUK63YAD6ITAVCNFSM6AAAAAATNFULECVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTONZQGUZDOOBYGQ> . You are receiving this because you were mentioned. <https://github.com/notifications/beacon/AXLUW3GODJEALXG7SHNFFNLYAD6ITA5CNFSM6AAAAAATNFULECWGG33NNVSW45C7OR4XAZNMJFZXG5LFINXW23LFNZ2KUY3PNVWWK3TUL5UWJTTJRAOIY.gif> Message ID: ***@***.*** ***@***.***> >

[git-kick]

Thanks for following this up.

Unfortunately, I cannot confirm PhilippSchlesingers observations:

• I restarted my PC
• logged in with my account (only)
• made sure only 1 Nextcloud instance is running
  but thumbnails disappear (after showing up for a very short time after opening Windows Explorer)

In general, I have a single user PC which has been showing the problem for months.

[PhilippSchlesinger]

@git-kick did you try removing and re-adding your sync folder?