First, I screwed up and messed up the permissions and ownership for a lot, if not all, the folders and files on my laptop that are stored on a separate partition (drive E) from the OS (drive C).
I do not generally store 'data' on C.
I tried various solutions and ended up re-installing the OS in the hope that permissions etc. were stored somewhere in there, it appears not, ho hum!
So, I have thus far "takeown"ed ownership of all files and folders on E via the elevated command line but was still denied access to some files. As I think there would have been 1000's of denied files it would have been tedious to go through them all and manually correct my mess.
Of the denied-files that I have looked at, the problem seems to be that there was only one group or user who had access and that 'person' is an unknown entity with a name that is either unknown or "S"-followed-by-a-number-string. I suspect that this entity is a legacy of my screwing up and might have been known to the old OS.
ICACLS "E:*" /grant "Sean":F /T
(from How can I change permissions for the folder including subfolders? ) I seem to have managed to add "Sean" and what appears to be the normal 'other' users and/or groups i.e. "USERS", "Authenticated Users", "SYSTEM" and "Administrators" to the folders and files and thus now seem to have access to all my files.
However, I would like to delete the 'troublesome' "S"-followed-by-a-number-string user or group but I do not know how to do that and am some what nervous about experimenting in case I screw things up again.
So could someone please tell me how to remove the user or group "S"-followed-by-a-number-string? Command line code would be appreciated.