This morning I turned on a computer that was completetly synced with Nextcloud last week. I realized that it started to explore files and it started to upload files to the server. According to the status bar, it tried to upload around 300GB of files (mostly pictures), which is basically the entirely of the nextcloud database. Around 1 file per second, that would take between one week and one month to complete.
I checked the files, and they are present both in the server and in the hard drive, so the only difference I found was the creation and modification date, that suddenly changed for all files in the Nextcloud folder in the client to 31-December-1069 at 19:00.
What could have happened? How could I prevent Nextcloud uploading all these files that already exist in the server? Is it possible to recover the previous creation and modification dates?