Windows 10: File Explorer not showing all files / Strange restore point

I have noticed a few odd things on my newly built computers:
1. When looking at the desktop through File Explorer, a number of shortcuts are not there. I can see them on the desktop, but not through the file explorer. Checking the security properties for these shortcuts, they have a user "Account unknown" , S-and a long number series of figures. This account has "special permissions". Visible shortcuts and files lack this strange account. What is this account and where does it come from? Is it possible to see also these files in File Explorer by some tweak? Why are they hidden there in the first place?
2. Right clicking the C drive on one of the computers, I find a previous version in the properties. OK. Apparently a system restore point was created last night, which is explained as "Installed Matrix". I did not install anything, and I have no clue what Matrix is. Anybody knows? Backing to this restore point apparently affects no program and there is no such program on the computer, I can find.

:)

 

Lost the entire directory

It basically explains itself if you test ride the 3 apps, which apparently you haven't yet done. By comparing ShadowCopyView and SystemRestoreExplorer you get to see the connection between Restore Points and Shadow Copies. Shadow Copies are the result
of creating Restore Points and are snapshots (backups) of your drive at the time of the restore point. ShadowCopyView shows all shadow copies all at once and lets you explore each of them. SystemRestoreExplorer shows the restore points and allows you to mount
them and open with File Explorer and you find that they actually do the same thing but using different methods. Apparently ShadowCopyView also allows to open a shadow copy with File Explorer but that currently fails.

 

Window 10 File Explorer results not correct

Current situation: File Explorer shows an empty folder. File Explorer Search shows five mp4 files in that folder. I cannot delete or move the files or the folder and I cannot open any of the files. I have rebooted and
tried any other solutions that I could think of without result. Incidentally, I uninstalled Cortana very soon after I upgraded from Win 8.1 to Win 10 last year and have used File Explorer successfully on a daily basis since then.

Recent events:

1. I detected this problem yesterday but I did not have enough time to deal with it then.

2. I tried to resolve it today by using system restore to return to a restore point prior to the problem occurring.

3. In the meantime Win 10 update had installed a critical update.

4. I started system restore with the intention of returning to one of the
restore points which I have created at least weekly or to a point that had been created automatically.

5. Restore would only allow me to undo the critical update, it did not show any of the other restore points.

6. I am familiar with how to show all the available restore points.

7. After rolling back the critical update I still cannot see any of the previous restore points.

Please help: I do not know if the File Explorer search issue could be resolved by using the restore point feature but I do need to resolve both issues. After much fruitless searching on the Internet I would be very grateful
for any assistance.