Thank you both for the ideas. But if I understood them correctly they would need a file-by-file intervention / restoration? And I reckon some items might get missed because hey became inaccessible?
With very important documents like tax forms or few existing photos of grandmother they would be doable. But when trying to check / recover for example copies of the same 20 000 songs from ~6 points of time, when having them also in 20+ other backups - it is simply not worth the time and energy. [Because what I lost / damaged are most likely some backups of various folders from the last 3 years from archive drive
A. I still have such backups [with different dates] on archive drive
B and the current versions]
I was thinking more around the lines of Everything trying to access all folders - and somehow marking those, which I am unable now to enter when navigating in FreeCommander or Windows Explorer. Because if I see such sub-folder then I will assume that also others got corrupted from that timestamped backup
I have tried using TreeSize Free [
https://www.jam-software.com/treesize_free] but it does not seem to have such capability
And coming back to your non-applicability of your solutions to my case: the problem with them is alike too hash values. Because what good will do me an info that folder X from 2022 01 01 has now a different value than when it was secured in form of a backup at that time, if it has 100 000 items? Or how would I compare efficiently 10 000 hash values of its sub-folders and then re-act to [lets assume] 1000 mismatches?
[After: dealing with backing up of data for over 20 years, experiencing this first (that I know of) failure of my backup system since 2014, participating in another discussion about data storage (
https://forums.tomshardware.com/threads ... ps.3805050) and discussing cons and pros of various approaches with ChatGPT - I know that I need to acquire another archive drive (
C) and also keep it off-line and never connect it at the same with
A and
B, while also keep burning Blu-ray discs. But the problem is I would need to buy a 22TB SAS HDD, while wanting at least 16TB SATA3 SSD. As for the
A, it is quite new and have not been even filled up, with my lost occurring to some accumulated software glitches]