I have my iTunes library file on a separate hard drive (which I believe may be the cause of the problem) and I have been trying to use it to synchronize with my Windows Phone.

I would like to first note that if I set up my phone to synchronize with 'Windows Libraries', then it works fine. This is however not ideal as I have categorised my music and made playlists etc, on iTunes.

Sync music, videos and more from: Windows Libraries

When I first link my Windows Phone to the Windows Phone App (for desktop) and select iTunes from the above selection, I get the following error message:

Something happened that we didn't expect.  But if you call support, you can tell them you saw this error code: 8300300B

After searching that error, I found the following forum threads:

I've tried the workarounds described in the above threads, however, they did not work for me.

If I ignore that error message, I see the expected interface, along with all of my iTunes library's media, however the 'Sync' button is greyed out.

Greyed out Sync button

I have tried some other things to try and fix this:

  • Removing the app's AppData folder
  • Uninstalling, reinstalling
  • Using the full-screen modern app (does not allow for iTunes syncing)

Just got Lumia 521 phones for the family. I found the same problem with the error 8300300B and the sync button greyed out when trying to sync to itunes. I tried many suggestions including the suggestion in the post above. None worked until I found a file in the C:\users\yourusername\appdata\local\Microsoft\Windows Phone called "lastexception" or something like that, which gave me the clue to the problem. In the text file somewhere, it says "Illegal characters in path." So I went through all the playlists in my Itunes and changed any playlist names which had potentially illegal characters (things like !>:/, don't know about &, but I changed it anyway). Then I deleted the iTunes library xml file and the windows phone folder in app data as suggested above. After doing this, the Windows Phone desktop app read the playlists without an error and the sync button was black. Yea!

I repeated this with my daughter's phone/computer, and all that was necessary was to change the playlist names to eliminate the illegal characters. After changing the playlist names only, the phone synced right up! Only a few hours wasted on Christmas morning, but problem solved. Hope this helps others out there!



  • Deleting the XML files will not harm your iTunes library.
  • It helps a lot to show hidden files.


  1. Close iTunes and the Windows Phone app (for desktop)
  2. Navigate to the directors containing your iTunes library (C:\Users\%USERNAME%\Music\iTunes by default)
  3. Delete the following files (some may not exist):

    • iTunes Library.xml - NOT iTunes Library.itl
    • iTunes Music Library.xml
    • iTunes Music.xml

    Screenshot of iTunes directory

  4. Naviage to %localappdata%\Microsoft and delete the Windows Phone folder inside of it. Deleting 'Windows Phone' directory

  5. Open iTunes again and give it time to recreate these files.
  6. Open the Windows Phone app (for desktop) and recreate the sync relationship with your phone.

Check out your playlist names. If there is a ", < or > and maybe other "special" additional characters the error accrues. In my experience ( ) [ ] ! § $ % & ? - + * . are accepted.

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