Sab sy pahly Ap logon nay (cmd) matlab command prompt ko RUN AS ADMINISTRATOR open krna ha us k baad Usko Command deni ha:

commands as follow:-

1st option:

manage-bde -lock x:

NOTE: jaisy main nay likha same aisy likhna ha space b aisy deni or x ki jaga jis drive ko bitlocker laga ha us ka likhna for example Drive D ha tou x ki jaga D likh dena ha CAPITAL LETTER Main......... or end pa COLON b dalna ha.......
and agar ye command na work kary tou second option command use karene

2nd Option:-

manage-bde -lock -ForceDismount x:

NOTE: x again drive k liye phir b koi problem ho tou i am availale

SHUKRIA