The Windows 10 boot and shared data partitions somehow got encrypted with Bitlocker (and thus are inaccessible from the Win 8.1 install) after a repair shop swapped the motherboard.

Fix BitLocker error E_FVE_TPM_NOT_DETECTED, The booting system doesn't have or doesn't detect a TPM in Windows 11/10.

Open the Windows search bar, type "BitLocker," click on Manage BitLocker and open it. Find your removable drive under Removable data drives – BitLocker To Go and select it.

5] Disable and Re-enable BitLocker. If none helped, try disabling and then re-enabling Bitlocker on your device. Doing so can help fix temporary bugs and errors. Here’s how: Open an elevated ...