After turning on BitLocker to encrypt your hard drive, it’s important to save a copy of the BitLocker recovery key in case you need it. If you’ve lost the recovery key created when you initially set up BitLocker, you can make a new copy of the key as long as you can sign into Windows 10.
If you forgot the password and lost the BitLocker recovery key for an encrypted drive, you would lose all your data on the drive. Because if you want to unlock a BitLocker-encrypted drive without password and recovery key, you have to format the drive. In order to avoid this tragedy, you should back up BitLocker recovery keys as soon as possible.
Step 1: Open the Manage BitLocker window.
Click on the Start Menu. In the search box, type "Manage BitLocker", then hit Enter to open it. Or you can go to This PC, right-click on the encrypted drive to select Manage BitLocker.
Step 2: Click on Back up your recovery key link.
Step 3: Select the way you want to back up your BitLocker recovery key for this drive.
It's recommended to save to your online Microsoft account. If you forgot the password, you could easily retrieve the BitLocker recovery key for an encrypted drive.
Click on Finish when you have finished backing up your recovery key.
Open the Command Prompt as administrator by pressing Win+X, and hit A on the keyboard. Run the following command and press Enter. Replacing C: with the letter of your BitLocker-encrypted drive.
manage-bde -protectors C: -get
You can find a 48 digit recovery key at the end. Note it down on a piece of paper or save it to somewhere secure and accessible.
Step 1: Click on the Start Menu. In the search box, type "PowerShell", right-click on PowerShell from the result list, then click on Run as administrator.
Step 2: In the PowerShell Window, run the following command and press Enter. Replacing F: with the letter of your BitLocker-encrypted drive.
(Get-BitLockerVolume -MountPoint F) .KeyProtector > $env:UserProfile\Desktop\BitLocker_Recovery_Key.txt
The BitLocker recovery key for that drive will be saved to a BitLocker_Recover_Key.txt file created on your desktop.