Check here: https://one drive.live.com/recoverykey to see if Windows automatically uploaded the key.
Or:
- Restart the system.
- At the Lenovo Logo keep tapping F2 or whichever key allows access to the BIOS screen.
- You will enter the BIOS screen
- Under General
- Select Boot Sequence.
- Select UEFI
- Select Apply.
- Under “Security” select TPM 2.0 Security
- Select Enable and click on Apply.
- Under “Secure Boot”
- Select Secure Boot Enable
- Select Enable.
- Click on Apply. Once these steps are done, restart the system.
OR:
On another device enter the website that comes up in the bitlocker screen. Your outlook email will come up, enter your email you use for windows and than password, it will than ask for you to choose one of your recovery emails, choose one and than confirm it by typing it in also, it will send you a code to that email, go to that email and than you have the code to enter. go back to the regular email and press you have code and than enter it. Than you will have 1 to 3 different bitlocker codes to unlock your hard drive and get back to windows. Try all 3 until one of them works on the bitlocker screen.
Big discusssion here https://www.dell.com/community/Windows-10/BitLo... on the Dell forum which may offer further suggestions for your Lenovo.