Where is your Quicken data file located? Specify the complete drive letter and path.
Do you use MS OneDrive to backup your data files to a Microsoft server? If so, configure OneDrive to NOT access your Quicken data files. Instead, configure Quicken to create backups every time you close a file or the entire Quicken program. Let OneDrive grab the backup files to make backup copies.
On some recent systems, MS OneDrive may be active by default, without the computer user having explicitly enabled and configured it and being aware of the fact that it's running all the time.