As stated in the user manual, this behavior is strictly expected.
The recorded files are DRM protected.
You can read them ONLY on the TV itself.
You won't be able to read them anymore if the TV mother board is changed in case of failure.

But you are happy because at least you can record...
I'm facing problem to record on a WD Passport 160GB (WDXMS1600TE), from a UE55C8700.
It does not format on the TV. It says "Cannot format"
Could you tell me the exect reference of your drive ?