Consider the following scenario:

• You are using a Trusted Platform Module (TPM) chip on a computer that is running Windows Server 2008 or Windows Vista Service Pack 1 (SP1).
• You put the computer to sleep, and then you resume it from sleep.

In this scenario, the following errors may be logged in the System log every 40 minutes:

Event ID: 13
Event Source: TPM
Event Type: Error
Event Description: The device driver for the Trusted Platform Module (TPM) encountered a non-recoverable error in the TPM hardware, which prevents TPM services (such as data encryption) from being used. For further help, please contact the computer manufacturer.

Event ID: 516
Event Source: TBS
Event Type: Error
Event Description: An error occurred while communicating with the TPM. The driver returned 0×8007045d.

The TPM driver and the TPM Base Services (TBS) log these errors when they try to obtain a random number from the TPM chip for the Windows operating system. The operating system uses this random number as an additional source of entropy when the operating system’s cryptographic methods generate random numbers.

Additionally, if the TBS sends other commands to the TPM chip after the computer resumes from sleep and if the operating system receives a “TPM_NEEDS_SELFTEST” response from the TPM, the operating system may be unable to use the TPM chip to generate random numbers for additional entropy.