Hi,
What error do you get when you try to format the drive? Usually you should be able to wipe the disk and install a fresh OS on it even if MDE is activated. It is an ordinary process if you need to rebuild a PC without having to collect any residing data. You could try to verify that BIOS/UEFI settings like Secure Boot does not interfere the format.
This is what I found in regards to that error:
https://kc.mcafee.com/corporate/index?page=content&id=KB69650
May be you could try rebuilding the MDE PBFS too:
https://kc.mcafee.com/corporate/index?page=content&id=KB71868
In case above information was useful or answered your question, please select "Accept as Solution" in my reply, or give a Kudo. Thanks!
Nino