win10 bitlocker enrypts partition after update

Question

one of my clients has an laptop with Win 10.

After the client run the latest Updates apparently BitLocker started to encrypt the files/Partition WITHOUT CONSENT and WITHOUT PROVIDING ANY RECOVERY KEYS.

When the client starts the laptop, a blue screen appears, asking for the keys.

The client NEVER associated/registered this laptop with an Microsoft-Online account, so the recovery keys can not be found there.

is there a way of decrypting?/recover the files? (Under Win 7 this seems to have been possible with the Passware Tool)

https://www.m3datarecovery.com/bitlocker-drive-data-recovery/unlock-bitlocker-without-password-recovery-key.html

other users seem to have the same problem:

"If there is no important data, you can directly format the BitLocker encrypted drive"

is unfortunately not an Option, since then the client would lose one year's work.

If this is correct - it is Win 10 behaving like ransomeware, only without Ransome, one of the biggest fail in Microsoft Windows history.

PS: of course client was informed about the importance of Backups (especially before Updates), Not everyone who owns a car can drive safely with it, but than still, the client is probably just one out of many experiencing this severe update "bug", what can the user do?

wait for quantum computers to become feasible to decrypt the data?

https://answers.microsoft.com/de-de/windows/forum/windows_10-security/bitlocker-verschl%C3%BCsselung-nach-updates/8f5556cd-7871-4412-8c63-5aef4a5248e2

"for the longest time my partitions were provided with an open lock AND a yellow warning triangle. However, I believe that in the end it was really only an open Castle. So actually before the Update was encrypted."

"My Surface Book 2 is also registered in my Microsoft ACC. However, the Key is missing. "You don't have any BitLocker recovery keys in your Microsoft Account."As I said, I can't remember being asked to write down or back up a BitLocker Key."

"When you sign in with a Microsoft account, Device Encryption is automatically reactivated."

"Yes, you understand that correctly. Encryption is automatically enabled on supported devices. It may not happen immediately, but only during the next maintenance, as long as the device is connected to the power. "

"The Surface Book 2 should come with Windows 10 Pro. There you can manage Bitlocker yourself by right-clicking on the C: drive, activate it accordingly and save your recovery key safely on another device."

Answer 1

All you need to do is leave recovery mode. Recovery mode gets triggered, when boot options change, when the boot order changes or when secure boot is toggled from on to off or reverse. You can leave it by undoing that change.

He never did this change? Well, possibly it went this way: the laptop was encrypted like forever, he does not even remember that some day, a Microsoft account was used, after all and he wouldn't know which one. He never noticed it being encrypted, since it uses TPM only encryption - passwordless. Now "with these updates" along came a firmware update (UEFI/Bios update), which triggered recovery mode. Short of providing the recovery password, he can only try to find out

->is the UEFI version quite new (possibly updated?) ->If so, can that be reversed ("bios downgrade") in order to leave recovery mode