If you see a yellow exclamation mark for ACPI\MSFT0101 in your Device Manager, follow these steps: What is the ACPI\MSFT0101 Device? - DriverIdentifier
: It holds the decryption keys for features like Windows BitLocker.
While the device itself has existed since the Intel Skylake era (around 2015), the 2021 landscape saw a surge in driver and firmware activity:
The ACPI MSFT0101 error is more than just an annoyance. A broken TPM means: -NEW- Acpi Msft0101 Driver 77 2021
: Check the HP Support Community or your specific model’s download page for the TPM 2.0 driver .
For users on modern operating systems like Windows 10 or Windows 11, there is usually no need to download a standalone "77 2021" driver.
Indicates the driver is missing completely. Follow the installation methods above. If you see a yellow exclamation mark for
: It is typically delivered through Windows Update under "Optional Updates" or "Driver Updates".
It enables TPM 2.0 support on newer motherboards (Intel Skylake and later), which is required for features like Windows 11 compatibility and advanced security. Operating System Context: Windows 10/11:
: An "Unknown Device" under Security Devices or System Devices showing hardware ID ACPI\MSFT0101 . A broken TPM means: : Check the HP
Because many Windows 10 users are finally upgrading to Windows 11 or Windows 12 (future). The original TPM drivers from 2018–2020 are still present on millions of PCs that have never been updated. The remains the last stable, universally compatible TPM driver for legacy Ryzen and Intel 7th/8th gen systems.
It provides hardware-based security for credential storage, key management, and encryption, essential for technologies like BitLocker.
The root cause? Microsoft’s inbox driver (provided via Windows Update) was often generic or outdated. It failed to properly initialize the TPM firmware interface on certain hardware combinations, particularly when the BIOS was in “Discrete TPM” mode vs. “Firmware TPM” (fTPM).
In a concerning incident from 2022 that highlights the potential for driver mismanagement, a driver automation tool mistakenly pushed a driver for the ACPI MSFT0101 device that was not intended for it. This incorrect driver was reported to cause serious system issues, such as black screens on wake from sleep and excessive battery drain. This is a powerful reminder to: