I bought a new computer earlier this year. I had been running the Installer version previously (I didn't understand when I first downloaded MusicBee that the Installer and Portable versions had the exact same functionality and features), and amassed a large library with custom tags and other customizations that were going to be a nightmare to bring across or replicate from the Installer version.
Several months prior to purchasing my new computer, I took a deep breath and took the time to implement what turned out to be the best possible advice - I converted to the Portable version. There are step by step instructions located elsewhere on this forum. While the conversion needs to be done meticulously (and there were a few minor tweaks after the conversion steps that I still had to discover and fix), once it's done, it's done. And life is much, much better.
Once I had the portable version installed, as all of my music is on external drives, it's simply a matter of remapping those external drives or using MusicBee's relink music file paths feature (I did the latter, worked perfectly, with a library of 1.5m tracks).