Windows 7: Bitlocker decryption stuck at 1% (despite use of -resume and -off)

Hi, all. I've got a 2TB drive -- a storage drive separate from my OS drive, that has whole-drive encryption via Bitlocker. Never had a problem with it.

Recently, I wanted to decrypt the drive and, about half-way through the process, received the same error message that many people here have reported: run chkdsk (and repair). I ran chkdsk and it said that it successfully moved data from a damaged sector to an undamaged one. On reboot, Bitlocker's decryption process successfully resumed, though there was no gui window, and I had to go into the command prompt to confirm anything was happening.

Everything looked great until I got to 1%. In command prompt, the manage-bde -status command now reports the drive's status is Decryption Paused.

I've tried forcing the process to continue by using the -resume and -off commands (e.g. manage-bde -resume <drive letter:>). In both cases, Bitlocker happily reports, "Decryption is now in progress", but a follow-up check on the status says otherwise (Decryption Paused). And the 1% remains stubbornly encrypted after many hours.

Any ideas about what could be done to get this drive to finish its work?

Thanks in advance for any ideas!