What might cause all files and folders after a certain timestamp to vanish from a folder and its subtree?
My daughter's computer has two disks: C and D. Windows installed on C. Some apps installed on D instead of C due to limited space on C.
After a hardware upgrade we performed a reinstall of Windows using "Reset this PC". We chose "Remove everything", which seems to have correctly quick(?) formatted C but left D intact. She continued using the computer, reinstalling several games, drawing tools etc.
This eventing, about a week after the reinstall, she looked for the first time after reinstall in a D folder where she regularly saves all her drawings and other files. To her horror it contains nothing dated after year 2019.
We've made sure her user account has full access to the D disk, including this folder, and that we're seing all files, including hidden and system files.
We've also searched the entire C and D disks for folders with that name (as well as the name of one of the most critical subfolders), but nothing was found. That check seemed relevant in case she accidentally dragged the folder to some random place without noticing, but I fail to understand how that would affect only newer files and not older ones.
Any ideas what might have happened or can suggest any actions that might help us recover the lost files?
(We are working on retrieving from backup, which is unfortunately a bit complicated for unrelated reasons, including lack of time for important system maintenance, which also possibly means that this particular folder might be missing from the backup. Hence this question...)
