I apologize if this is in the wrong place, but I couldn't find anywhere else that seemed appropriate for these questions.
My classmate has a 512GB USB drive that he had formatted as exFAT and encrypted with BitLocker To Go. Something then happened with his Windows OS that made him unable to decrypt his device. I believe he said that he upgraded from Windows 8.1 to 10, but I honestly don't remember.
In any case, he said that he read online that the only way to recover his data was to format the drive. So he did. And, of course, his data is now gone. I told him that I'd look into trying to recover the data.
What I have found so far is not promising. I'll assume that anyone who answers or comments knows how BitLocker works, so I'll jump to the questions.
1) Having read bitlocker and data retrieval, I am wondering if it is possible to recover the still encrypted data, without decrypting it? I know that the file headers are encrypted so traditional data recovery software isn't going to work, but is there any way for any program to scour the raw bits and bytes to determine the start and end of a file, even if it can't decipher the actual data?
1a) If the encrypted data is recoverable, will it be possible to decrypt the data with his password, assuming he knows it?
2) If there's no way to recover the encrypted data without decrypting it first, will a program such as Diskinternal's EFS Recovery work, assuming he knows his password? BitLocker Password Change talks about an encryption key being stored in the volume header, so it leads me to believe that the it's not possible, since the volume header was overwritten during the format. But, I don't know how BitLocker works beyond some cursory reading, so maybe it's still possible.
I've spent the better part of two weeks trying to recover the data, to no avail, so any answers would be appreciated.