I can't recall seeing anyone on the forum with a similar issue.
What version of MB are you using? (Help > About)
How was MB installed? (Store, Installer, Portable)
Try using the Portable version available from the download section of the website. Install it in a directory outside of Windows control, such as C:\MusicBee. Once installed apply the latest 3.5 patch following the link and instructions in my signature below.