ProSelect finds out about your iTunes music by reading the file iTunes Music Library.xml or iTunes Library.xml (used in the latest versions of iTunes) which iTunes updates whenever you make changes to any music.

In the latest versions of iTunes, you need to enable the saving of this file by turning on Share iTunes Library XML with other applications in iTunes Preferences (under the Advanced Tab). 

ProSelect assumes that this file is located in it's default location on your Mac or Windows PC which is inside the Music folder of your Home account (ie your accountName folder):

While you can move the iTunes Music file somewhere else, it's probably best to keep it in the above location to avoid problems with ProSelect locating the file. If you have moved it (and put it back) then make sure iTunes is pointing to the correct location by:

1. Opening iTunes Preferences,
2. Clicking on the Advanced tab and
3. Setting the "iTunes Media folder location" to the default location. It should say something like:

Use the Reset button to set it to the default location.

Support for iTunes Library.xml

If your version of iTunes is saving its data into the latest iTunes Library.xml file (instead of the earlier iTunes Music Library.xml file) then your best option is to be using ProSelect 2015r2.14 or newer as this supports both files.  Otherwise, if using an earlier version of ProSelect, you can copy your iTunes Library.xml file to iTunes Music Library.xml (keep it in the same folder). Note: you will need to do this every time you make any changes in iTunes else those changes won't be reflected in the copied file.

Choosing another iTunes folder location

If the above does not solve your problem, you can force ProSelect to look in another location for the iTunes data by holding down the Alt Key (on Windows) or the Option Key (on the Mac) when you click the Add Music Group from: iTunes Playlist button. This will allow you to navigate to your new iTunes folder location and select it. 

IMPORTANT: Make sure that you select the iTunes folder itself NOT the iTunes Music folder which is inside the iTunes folder.

If you are using ProSelect 2015r2.x, make sure that you update to ProSelect 2015r2.14 or newer as this fixes a bug where the Select iTunes Location selection dialog would open behind the other open windows rather than on top.