My x7 isnt recognized by any pc what should i do?

My x7 isnt recognized by pc anymore i have tried different pc's and upgraded the frimewire to last version plz help me fiio plzzzz :(((

i tried to reconnect x7 to my pc for several times but the 'upgrade now' button wont be highlighted what should i do? :(

 my t90 had exactly the same problem as you said except it was at left side. as you said it just happened at some songs for example the song "hello" from Adele. that time i drove them directly from fiio x3 2nd. So i returned them and got a new one. the second pair didnt have that problem at all...

Hi guys, has anybody compared crack and a20 for the t90? right now im using it with fiio x3 2nd G.

I have had msr7 for about 5 month and i must say they are great as a closed back headphone for the price asked. Im using it with fiio x3 2nd. Now im looking to upgrade my cans. Has anybody here compared msr7 with t90?