[Bug]: Desktop Client deleting files after DLL crashing

[lorenzodav-sys]

⚠️ 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

After re-installing the Desktop Client from the previous desktop computer to a new notebook with Windows 11, once completed the synch with the files hosted in the remote server, the application has encountered an error and then under my account name has started massively deleting shared files apparently at random.

The files have been moved in the recycle bin of the server and subsequently restored.
According to the system log the error has been originated by nextcloud_csync.dll - error code 0xc0000005 - ID of process which has generated the error 0x0xA54

Steps to reproduce

I had a fresh installation on a Windows 11 Notebook of the Desktop Client. The synch with the server was successful, but at a certain point a DLL in the synch module crashed and in less than 30 minutes as per server log my user was deleting gigabytes of files.

Expected behavior

The files shouldn't have been deleted randomly.

Which files are affected by this bug

nextcloud_csync.dll

Operating system

Windows

Which version of the operating system you are running.

Windows 11

Package

Official Windows MSI

Nextcloud Server version

28.0.5

Nextcloud Desktop Client version

3.15.3.65019

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 Enabled

Are you using an external user-backend?

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

Nextcloud Server logs

Additional info

The notebook is HP ProBook 440 with Windows 11 installed - the computer was connected via Wi-Fi.
The problem at the moment has apparently been solved for now uninstalling and reinstalling the Desktop Client

[camilasan]

The crash could have corrupted the database? The only way to check why it was deleting files is to check the logs.
And definitely the server logs could also show what happened.
After reinstalling did you have to setup your account and folder again?

[lorenzodav-sys]

Yes, after re-installing I had to setup my account and folders again. It seems to be working fine for now. The only server log I can access said that a certain moment "[my username] has deleted [blank space]" (this happened at the same moment when the Windows log says nextcloud_csync.dll has crashed) - then the online log said I was massively deleting files (which actually ended up in the bin).