Couldn't update placeholder info; Nextcloud-3.9.1-x64 Windows client

I installed (automatically, for laptop computer 1, sometime end of July 2023 after the 23rd) the latest Windows desktop version, Nextcloud-3.9.1-x64.

Since I go back and forth between this laptop, that I leave to work from home or travel for my job, and a desktop in my office, I like to keep my working files on a Nextcloud server run by my university. All the IT staff is on forced vacation from August 1st to August 16th.

After having noticed that the latest version of a document in a shared folder belonging to a colleague, that I’d worked on from the laptop, had not been properly synced, I looked more closely at my tray icon. I had probably left it open on my laptop while I opened it at work, or something like that. Other files sync appropriately.

However, I have a terrible problem since I panicked and changed the properties to keep a copy of all files locally on the laptop, though I’d been working with virtual files. This concerns over 60 Gb of data, some shared with me, most hosted by me.

I then realized that it would be silly and chose to “leave on the server” but then retain locally the important folder I am working on at the moment, having it sync. However, I believe this has made it now necessary to change all the properties for every single file, or so it appears at least in the /Shared/ folder. I mean, modifications for 29 Gb on over 30K files?


And then I get this error message, reminiscent of the bad old days when I also reset the date for every single file on the server to 01/01/1971. It checks first for modifications on every single file. When that’s done, I get the following, as well as creation of a new folder, Nextcloud\Shared_gsdata_


Could you suggest a fix or a secure work-around, please? Thank you!