Bitlocker for Fixed Drive - What happens if you reformat your boot drive?

[Suspicious-Teach8788]

I have Bitlocker setup for my boot SSD and a fixed drive. I have no TPM so Bitlocker for the boot drive = password.

However the data drive/fixed drive is set to unlock automatically once the system is booted. I assume that just means the drive stores some data in the Windows installation for automatic unlocking?

Well what happens if I want to reformat my boot drive? What happens the data drive? Should I turn off Bitlocker first? I do have the backup key stored safely so I assume I should be able to access it, but I haven't found good documentation.

 

[PliotronX]

It should act like inserting a BL removable drive, it will tell you that its encrypted and needs the password or key and then you can set it to unlock automatically at boot up. That's my theory but I have not done this with a fixed drive.

 

[Suspicious-Teach8788]

It should act like inserting a BL removable drive, it will tell you that its encrypted and needs the password or key and then you can set it to unlock automatically at boot up. That's my theory but I have not done this with a fixed drive.

Hmm makes sense but since the only key is my backup key that's why I was a bit concerned. The last thing I'd want is for my data to be lost

 

[PliotronX]

Yeah dude, I feel the same and would play it safe by fully decrypting for the new windows

 

[Suspicious-Teach8788]

Ok just an update and maybe hopefully information for those who are searching on this topic in the future--you are allowed to create a Bitlocker volume for fixed storage drives with several methods of unlocking:

1. Passphrase
2. Smart card
3. Auto unlock from boot drive.

I assume there's more options if you have a TPM but I do not. I only checked #3 because this is a non-boot drive. It took like 3 or 4 days for a 4TB drive to finish encrypting, but now that it's done I see the option to turn off Auto Unlock. It did warn me to do so I need to add an additional method of unlocking (i.e. passphrase or smart card). I added a passphrase and feel a lot better now.

I assume at this point if I reformat my boot drive as long as I keep the passphrase handy I can easily mount and unlock this secondary drive, and probably turn off automatic unlocking easily. I would assume I should still be able to mount the drive using the backup key too, but given that from a UI/UX perspective they likely wanted you to use a passphrase/smart card/TPM method it's probably safer in terms of keeping my data accessible that I have enabled the passphrase option.

Edit: BTW I should clarify I was asking this because I was thinking of swapping my motherboard out for a different model. Given motherboard swaps are usually messy in terms of drivers and what not, I figure a reformat would be the best way of the boot drive, thus leading to this conundrum.

Still deciding on the motherboard situation, but if I do get to the reformat point I'll update this thread with my results.