I uninstalled Kaspersky Total Security. Set Windows Security Up. Scanned a document in Adobe Acrobat. Tried to save it but got the message it was “ready only”. Tried to save it several different ways. Same thing. Opened Lightroom and it could locate my Lightroom Catalog. Uninstalled Lightroom and tried reinstalling many times. Installation would stop at 91% every time. It appeared to be a problem with access to my C drive/documents/user.
so this is where I went further than I should have. I think I restricted access to the entire C drive. Now after I sign in with my Windows ID, just get a black screen with my white mouse arrow. Just updated Windows 10 Pro a couple days ago, too.