When I have upgraded from WIN 8.1 to WIN 10 all data files under "Documents" have become read only which makes it impossible to update or save new files. How do i change it to normal again?
This seems to be an issue for some people upgrading to Windows 10. This might help:
Right-click your Documents folder and open its Properties.
Uncheck Read only.
Open the Security tab and click the Edit button below the user list (it might be labelled differently, I'm translating from a German system).
Select your user name from the list and check all checkboxes in the left column.
Close both windows by clicking OK, then check to save changes to your files again. If it fails, open the directory, select all files (Ctrl + A), right-click them and repeat these steps.