Quick Answer
Restart the TBS (TPM Base Services) scheduler service and set its startup type to Automatic. If that fails, check for corrupted TPM drivers or a BIOS setting disabling TPM.
Why This Error Happens
You're seeing 0X8029020A because the TPM scheduler service (TBS) decided to take a nap. This usually happens after a Windows update, a power outage that didn't shut down cleanly, or when some security software messes with TPM permissions. I've seen it most often on Dell OptiPlex 7080s and Lenovo ThinkPads after the KB5023706 update from March 2023. The error pops up in Event Viewer, during BitLocker recovery, or when you try to use Windows Hello.
Fix Steps
- Open Services — Press Win + R, type
services.msc, hit Enter. - Find the TBS Service — Scroll down to TPM Base Services. Double-click it.
- Check Startup Type — Set it to Automatic from the dropdown. If it's already Automatic, leave it.
- Start the Service — Click Start. If it's already running, click Stop and then Start again to reset it.
- Apply and Exit — Click Apply, OK, then close Services.
- Reboot — Restart your machine. Test if the error repeats.
Alternative Fixes (If the Above Fails)
Check TPM in BIOS
Sometimes Windows can't start the TBS service because the TPM chip is disabled in BIOS. Reboot, mash F2 or Del (varies by manufacturer), find Security settings, enable TPM (often under Intel PTT or AMD fTPM), save and exit.
Clear TPM (Destructive)
This wipes your TPM keys—BitLocker recovery keys, Windows Hello data, all gone. Only do this if you have recovery keys backed up. In Windows, go to Settings > Update & Security > Windows Security > Device Security > Security Processor Details, click Security processor troubleshooting, then Clear TPM. Reboot twice.
Run SFC and DISM
Corrupted system files can stop TBS from starting. Open Command Prompt as admin, run:
sfc /scannowThen:
DISM /Online /Cleanup-Image /RestoreHealthReboot after both finish. This fixed it for a client with an HP EliteBook 840 G8 that kept losing TPM after updates.
Prevention Tip
After you fix it, check that Windows Update isn't messing with TPM drivers. Go to Settings > Windows Update > Advanced options > Optional updates and look for any TPM driver updates. Also, consider disabling TPM automatic driver updates via Group Policy if you're in a business environment—prevents this from recurring after patches.