After Bitlocker Decrypt Disk is Write Protected

Question

I have an internal HDD that was previously a Win7 boot disk and was encrypted with Bitlocker. I replaced the old computer with a new one with a new HDD. I moved the old Bitlocker encrypted HDD to the new system and decrypted it. Now the HDD is write protected. Bitlocker even gave a message after decryption saying that the HDD would be write protected. How can I remove the write protected status short of reformatting the disk (which I don't want to do)?

I have changed the Group Policy for Bitlocker drives, and I have used diskpart to remove the attribute on both the HDD as a whole and on the partition. Nothing has worked.