I used my ThinkPad on my job where it was part of a domain. Now I am retired, but could keep my old ThinkPad. I had all my personal data on D: including Desktop, Documents etc.
I continued using it for half-a-year, then Microsoft started complaining about the Windows not being genuine.
I decided do cut all bonds to my computer's past and I pulled the computer out of the domain (which it had not been connected to for half-a-year anyway). I also installed a fresh version of Windows 7 Pro on my C-drive, and right now I am making a last-minute free upgrade to Win 10. Everything works fine, except that I probably was too tired when I stupidly pulled my computer out of the domain without copying my data on the D-drive to a safe place first. I forgot to take into account that my data folders are locked to the domain user who doesn't exist anymore. All permissions and ownerships now belong to a nonexisting user on a (an seen from the computer) nonexisting domain. I have tried to take over the ownership, but I am not allowed to do that - even as a local administrator. It looks like I have to be administrator of the old domain too.
The word CACLS comes to my mind, but I have forgotten too many details of the possible work-arounds to be able to handle this myself, so I need your help.
In order to fascilitate the description in your answer, here are some names:
Old user: kf on the domain UNDERVISNING
New user: knud on a stand-alone computer
The locked data are subfolders to D:\kf
And yes, it is my own personal data I am trying to hack my way into!
Thank you for helping!