No entanto, ainda são permitidos apenas 0-9 caracteres. Por que isso acontece?
A configuração que você alterou se aplica apenas aos novos pinos de inicialização do BitLocker.
Existing drives that were protected by using standard startup PINs are not affected.
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Important
Not all computers support enhanced PIN characters in the preboot environment. It is strongly recommended that users perform a system check during the BitLocker setup to verify that enhanced PIN characters can be used.
Fonte Configurações da Política de Grupo do BitLocker
O que mais pode ser feito?
Você pode descriptografar a unidade e criptografá-la novamente, o que exigirá que você configure outra senha.
Decrypting the volume means that BitLocker protection is removed from the computer and the drive is decrypted, which can be time-consuming. When you decrypt the volume, all of the information stored on that computer is decrypted.
If you decide to turn BitLocker back on, it will either use the TPM on that computer or it will require you to set up another password.
Configurações da Política de Grupo do BitLocker
This policy setting permits the use of enhanced PINs when you use an unlock method that includes a PIN.
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When enabled
All new BitLocker startup PINs that are set will be enhanced PINs. Existing drives that were protected by using standard startup PINs are not affected.