Hi,

in WinPE it is possible to read bitlocker encrypted drives.

Check state
manage-bde -status c:

If the drive is only protected by a password use
manage-bde -unlock c: -pw

If bitlocker uses the TPM chip on the mainboard use the following command line. The rp option requieres the Recovery Key with is build during the activation of Bitlocker on the specfied volume.

manage-bde -unlock c: -rp 122345-456788-233455-345356-546466-456356-345634-967657

When TPM is used and a RecoveryKey file is created during activation is this your command

manage-bde -unlock c: -rk C:\RecKey.dat

For further details se the help page

manage-bde -unlock -help

Michael