Thank you everybody. I will try to clarify the question.
Let me sumarize the situation: I have two PCs, say PC1 and PC2, both with Windows 8.1. In PC1 I installed MusicBee 2.5, and in an external USB drive MusicBee 2.5 Portable, to be used mainly with PC2.
In PC1, the program is installed in C:\MusicBee. There is a second MusicBee folder in:
C:\Users\GH\AppData\Roaming\Microsoft\Internet Explorer\QuickLaunch\Music and Audio\Audio
There is not other MusicBee folder in PC1.
In the external USB drive MusicBee 2.5 is installed in F:\MusicBee, and there is no other MusicBee folder in F:
I have a quite large collection of albums in external USB drives, organized in folders and sub folders. After installing MusicBee in PC1 I realized that there exists a portable version, and I decided to install Portable MusicBee in the external drive(s), to use it mainly with PC2, but perhaps with both PCs. In both cases I begin to scan some (not all) of the folders in the external drive (there are many folders), and after that I have a considerable task puting in order many errors (duplicate albums, tracks which belong to album A that appear in album B, and so on). I think that many of these corrections are made in the individual file's tags, but some data must also be in some MusicBee file, because when I run MB only the Library containing the scanned folders appear. Say: when I run in PC1 the installed MB I find only the folders I scanned with this MB, but when I run (always in PC1) the portable MB I find only the folders I scanned with portable MB.
Which are these MB files and where are they?
THE PROBLEM: I want to install Portable MB3 in the external USB drive without losing the work done. Should I install it in the same MusicBee folder where I installed Portable MB2.5?