I messed up by changing who had access to LibreOffice. Do not know how to fix
First thing to try: Run LO as the Administrator user (Right click and select Run as Administrator.)
If that doesn’t help, and you don’t remember the steps you performed to revoke rights, you can try to reinstall.
Run the installer as Administrator.
You may need to run it twice, first uninstall (if asked what to remove, remove everything ; “everything” in this case does not include your documents), then install. Run as Administrator the second time too.