Back up your BitLocker recovery key in Windows 10/11. | Microsoft Support Article

Back up your BitLocker recovery key. BitLocker is the Windows encryption technology that protects your data from unauthorized access by encrypting your drive and requiring one or more factors of authentication before it will unlock it. In normal use BitLocker simply unlocks when you successfully sign into Windows. However, Windows will require a BitLocker recovery key when it detects a possible unauthorized attempt to access the drive. It's critical that you have a backup copy of this key. If you lose the key, Microsoft support isn't able to provide it, or recreate it for you. In most situations your key is backed up when BitLocker is first turned on, but it's a good idea to do a backup of your own. Here's a link to step-by-step instructions to bakup your Bitlocker recovery key: https://support.microsoft.com/en-us/windows/back-up-your-bitlocker-recovery-key-e63607b4-77fb-4ad3-8022-d6dc428fbd0d