I had the same issue following an essential BIOS update flagged up in Dell Support Assist. Our IT dept couldn't resolve it, but I managed to by doing the following: -

BitLocker is prompting for a Recovery Key and you cannot locate the key

* Restart the system
* At the Dell Logo keep tapping F2
* You will enter the BIOS screen
* Go to Secure Boot header, expand and select Expert Key Management
* Click the Restore Settings button
* Select Factory Settings
* Press OK
* Exit the BIOS and restart

Windows should now launch as it did before, even my last browser session appeared and lost nothing from c:\ drive!

Still not resolved? Use the "Get Help Now" option at the bottom right to chat with a Dell technician right away.

Video on TPM/Bitlocker:

Before we start troubleshooting, please notice this:

Beginning in Windows 8.1, Windows automatically enables BitLocker Device Encryption on devices that support Modern Standby. With Windows 11 and Windows 10, Microsoft offers BitLocker Device Encryption support on a much broader range of devices, including those that are Modern Standby, and devices that run Windows 10 Home edition or Windows 11.

Unlike a standard BitLocker implementation, BitLocker device encryption is enabled automatically so that the device is always protected. The following list outlines how this happens:

• When a clean installation of Windows 11 or Windows 10 is completed and the out-of-box experience is finished, the computer is prepared for first use. As part of this preparation, BitLocker Device Encryption is initialized on the operating system drive and fixed data drives on the computer with a clear key (this is the equivalent of standard BitLocker suspended state). In this state, the drive is shown with a warning icon in Windows Explorer. The yellow warning icon is removed after the TPM protector is created and the recovery key is backed up, as explained in the following bullet points.
• If the device isn't domain joined, a Microsoft account that has been granted administrative privileges on the device is required. When the administrator uses a Microsoft account to sign in, the clear key is removed, a recovery key is uploaded to the online Microsoft account, and a TPM protector is created. Should a device require the recovery key, the user will be guided to use an alternate device and navigate to a recovery key access URL to retrieve the recovery key by using his or her Microsoft account credentials.

Microsoft recommends that BitLocker Device Encryption be enabled on any systems that support it, but the automatic BitLocker Device Encryption process can be prevented by changing the following registry setting:

• Subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\BitLocker
• Value: PreventDeviceEncryption equal to True (1)
• Type: REG_DWORD

From Overview of BitLocker Device Encryption in Windows

Usefull troubleshooting to bypass the Bitlocker screen so you can disable (not recommended by Microsoft) the same inside Windows:

1. Ensure the Secure Boot is ON.
2. Load BIOS defaults* and check in PTT On under PTT Security.
3. Load BIOS defaults.

Load BIOS defaults

1. Enter System Setup. (Tap the F2 key at the Dell logo)
2. Press the up- and down-arrow keys or use the mouse and select Load Defaults.
3. Press. ENTER then select Yes.
4. Press Esc or select Exit. If prompted "Are you sure you want to exit?" Select Yes.

Ultimately, if none of the above steps work, an OS reinstallation would be the final recommendation.

Helpful video:

If still under the purchased warranty, click the "Get Help Now" icon on the right to start a live chat session.