Same File Doesn't Work On Different Harddrive


i always used my older WD Book 500 GB Drive to play my mkv files etc. and they played just fine. Now i moved them as a back up on my WD Essential 1,5 TB Harddrive and suddenly the same files won’t play anymore. It tells me that the file isn’t supported even though i know for a fact it is, cuz it plays just fine on my other hdd.

any ideas? i’m using the older WD Digital TV box. 

Thx in advance 

 Do they play on your computer?  You might reformat the drive, just in case the partition has been damaged.