Suface laptop device appears then disappears on account page

If the Surface device disappears from the Microsoft account device list, the BitLocker recovery key may still be available separately. Check the recovery key directly at https://account.microsoft.com/devices/recoverykey and also check any work or school account that may have been used with the device.

For Surface devices, the device can be registered manually by serial number:

1. Go to https://account.microsoft.com/devices and sign in.
2. Select Register device.
3. Enter the Surface device serial number.

If the device still appears and disappears, there is a reported issue where devices that are correctly linked do not consistently show in the Microsoft account device list.

If the laptop is currently at a BitLocker recovery screen:

1. Enter the 48-digit BitLocker recovery key. Hyphens are optional.
2. If the correct key is accepted, Windows should start.
3. If the problem started after a Surface UEFI or TPM firmware update and the device keeps prompting for the key, boots into UEFI, or loops restarting, use the recovery key and a Surface recovery image to boot to Troubleshoot > Advanced Options > Command Prompt.
4. Run:

manage-bde -unlock -recoverypassword <password> C:
manage-bde -protectors -disable C:

This disables BitLocker protectors on the boot drive so the device can boot again. This reduces protection on the device, so BitLocker should be re-enabled afterward from Start > Manage BitLocker.

If the recovery key cannot be found, Microsoft Support cannot retrieve, provide, or recreate a lost BitLocker recovery key.

References:

• Manage devices used with your Microsoft account
• Missing Devices - Microsoft Q&A My Computer Is "NOT" shown on the Devices Tab in my Microsoft Account Page.
• registered device not showing up in Microsoft "device" section - Microsoft Q&A Just got my surface laptop 13 recently , and I replace it with a bigger ssd , since after the new ssd install with surface recovery image, I not able to see my device showing up in my Microsoft account.
• Windows devices for home users, businesses, and schools with Microsoft-managed updates
• Prompted for BitLocker recovery key after installing updates to Surface UEFI or TPM firmware on Surface device