1. Decide your file naming convention and stick with it!

 

Why is this important?

There are multiple ways of having your media added to iTunes.  Some examples are listed below:
 
 
The default settings in iTunes mean that if you add content to iTunes, iTunes will reference the source content within its database.  For example, if you add a file d:\serverfolders\music\mysong.mp3 whilst running iTunes interactively (File menu / Add File to Library), this full path will be stored within the iTunes database.
 
If you subsequently set up an iHomeServer Watch Folder using a UNC path to your server's music folder, eg \\whs01\music, iHomeServer will scan the folder, find mysong.mp3, and attempt to add it to iTunes.
 
Even though d:\serverfolders\music\mysong.mp3 and \\whs01\music\mysong.mp3 is actually the same file, iTunes doesn't know this so will add both files independently, meaning you will get duplicates tracks.
 
Similarly, if a M3U playlist contains absolute filenames that refer to the same physical file using a different root path, when iHomeServer attempts to automatically add playlist referenced tracks to iTunes, iTunes will not know that the file has already been added and add the content again.
 

Recommendation

If you are using iTunes on a server, it is usually simpler to ensure all aspects of your media library reference files using a UNC pathname, such as \\whs01\music\mysong.mp3.  This means, for example:
 
 
These are just recommendations and local paths can, of course, be used if you understand how your media is structured, or for example, only use Watch Folders to add media.
 
Important Note
One other thing to note - if you have media on other servers, eg NAS servers, once again, the UNC path should be used.  If you normally access your remote media via a mapped network drive (say m:\), then you might be tempted to create a Watch Folder using this same mapped network drive.  However, as iHomeServer runs in the context of a Windows Service, these mapped network drives are not reliably available as they are user-session specific.  If you add the Watch Folder using the equivalent UNC path, this will be fully available from the iHomeServer service context.