It turns out there are 2 versions of wmp ver.12; one is for Win7 and the other is for Win8/8.1.
12.0.7601.1754 WMP 12 for Windows 7 12.0.9600.17031 WMP 12 for Windows 8.1 and Windows 8
So, can you please provide the EXACT version number you have on your system?? Here's a link to help you find where to look for this information: https://support.microsoft.com/en-us/kb/190990
I don't have a Win8/8.1 system to test this on for you at the moment. I had an 8.1 laptop just go out my door this morning, but I forgot to check the WMP for you for that setting.
You might try and download the NEWESTversion I have listed above for you. Notice at the end of the version number, your version says ".16578", and mine shows ".17031". The version I have posted for you is NEWER than the version your are running. I suggest in the meantime, you download and install that version (12.0.9600.17031 WMP 12 for Windows 8.1 and Windows 8).
You may find some useful information there. If you still can't get an answer, I might suggest you contact Microsoft Support with your specific question, and see if they can help you. Their E-mail support is Free, and they usually get back to you with 24-48 hrs. with a response.