I installed long time ago "Easy Context Menu" and added when i press right click, the option to "take ownership" from a folder/disk.
Also long time ago I had plugged in my old C:/ HDD from my old system, just to read some files, never had problems.
Then one day, I randomly looked into the HDD without a big reason, and one folder didn't open, and i took ownership.
After restart, when I tried to download from FF but it didn't let me and said something like no enough permission. When pressing windows start menu, a banner pops up where he wants to logout to fix startmenu but after logout nothing changed.
I made a new admin user and another user which i wanted to maybe change to.
I was stupid enough trying to fix after midnight, und i guess i fucked it up.
I have once run "takeown /S system /U username /P password /F "C:/" ", after restart, firefox doesn't open anymore.
Then I tried reseting permissions with "ICACLS * /T /Q /C /RESET", now start menu firefox opens but all letters are kinda gone, at leat at every windows program and edge doesn't open, FirFox seem to work. But all Windows application have only few icons left nothing else.
I read afterwards with reset the he might not know which user owns what.
When I run icacls reset again after, I deleted 2nd User and Admin, then it is technically like before only my original user left. So after deleting all other users it should be more clear that he owns everything what is possible to own as normal user, and everything higher maybe for administrator or UAC style, meaning no own admin account only elevating kinda standard user for several tasks to admin?