How to create more than one iTunes Library one the SAME computer

It is possible to create 2 different libraries in iTunes. I have done this in the past by using 2 different hard drives (internal/external). You can do it on the same drive too, although I've never done it this way

In order to choose a different library altogether you need to hold down the SHIFT key whilst launching iTunes and keep it held down until you get a pop-up dialogue box.

You will get options:
1 - Quit
2 - Choose Library
3 - Create Library

Select option 3 and "Create" a new library. iTunes will ask you where you want to save this library to. I recommend a different folder than the one in which you keep your main library as iTunes will create a new Itunes Library.itl file and you don't really want to confuse the two by keeping them in the same folder.

Once you have selected a new folder to save your music to, you can launch iTunes in future by using the SHIFT method and point it to the new iTunes Library file you just created above. If you don't use the SHIFT method iTunes will automatically open your original and default library

NOTE: if you have some music in your original library that your wife likes, you can copy that over to the new folder too


You might need to configure the iTunes preference pane to point to each drive directory (under Advanced - Importing):

For example:

C:\My Music\iTunes Folder

C:\My Documents\My Wifes Music\

You should already have something similar to the first example for your existing library.

Source(s):

http://support.apple.com/kb/HT1589