Synchronisation error and desktop no displaying

Hello,

Since the upgrade of my flatpak Nextcloud Desktop 4.0.2 (KDE), I have a notification telling me that I have a synch error.
My installation is in French, so all the displayed messages I mention below are translated from French, there can be some mismatches with the proper English sentences, but the meaning should be the same :
When I click on “Open the NC desktop” on the drop-menu, nothing appear.
If I do that on “parameters” , then on my account icon, it does say “there are non solved conflicts , please click for more details” .
If I click, all the synch folders appear, but none is highlighted to tell me where the error is coming from.

I was on NC30, I did the upgrade to NC32, nothing changed.

If I do a cat /var/log/syslog | grep nextcloud I have :

2025-12-02T09:05:06.066930+01:00 USER systemd[2890]: Started app-flatpak-com.nextcloud.desktopclient.nextcloud-3482.scope.
2025-12-02T09:05:08.634105+01:00 USER flatpak.desktop[3725]: nextcloud.gui.application: Migrating old config from “/home/USER/.var/app/com.nextcloud.desktopclient.nextcloud/data/Nextcloud” to “/home/USER/.var/app/com.nextcloud.desktopclient.nextcloud/config/Nextcloud”
2025-12-02T09:05:08.634188+01:00 USER flatpak.desktop[3725]: nextcloud.gui.application: Failed to move the old config directory to its new location ( “/home/USER/.var/app/com.nextcloud.desktopclient.nextcloud/data/Nextcloud” to “/home/USER/.var/app/com.nextcloud.desktopclient.nextcloud/config/Nextcloud” )
2025-12-02T09:05:08.634240+01:00 USER flatpak.desktop[3725]: nextcloud.gui.application: Will move the individual files QList(“Clos Stand By_sync.log”, “Commentaires Itinéraire Route_sync.log”)
2025-12-02T09:05:08.634275+01:00 USER flatpak.desktop[3725]: nextcloud.gui.application: Fallback move of “Clos Stand By_sync.log” also failed
2025-12-02T09:05:08.634481+01:00 USER flatpak.desktop[3725]: nextcloud.gui.application: Fallback move of “Commentaires Itinéraire Route_sync.log” also failed

Any help would be welcome.

:folded_hands:

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Desktop version : Nextcloud Desktop 4.0.2 (KDE)
Nextcloud Hub 25 Autumn (32.0.2)
Ubuntu 24.04

I did a cp -R .var/app/com.nextcloud.desktopclient.nextcloud/data/Nextcloud/ .var/app/com.nextcloud.desktopclient.nextcloud/config/Nextcloud/ with no results