Fix TPMAPI_E_INVALID_ENCODING 0X8029010E Error

Quick answer: Clear the TPM via Windows settings or BIOS, then update the TPM driver. That fixes 90% of these errors.

Why you're seeing this

TPMAPI_E_INVALID_ENCODING (0X8029010E) means Windows can't read the TPM binary blob — basically the TPM chip's internal data is scrambled. This happens most often after a BIOS update goes sideways, or when you switch from UEFI to Legacy boot mode. I've also seen it on Dell Optiplex 7080s and Lenovo ThinkPads after a Windows 11 feature update. The culprit is almost always a corrupt TPM driver or a partially-bricked TPM chip.

Fix steps

Clear TPM from Windows
Go to Settings > Update & Security > Windows Security > Device Security > Security processor details > Security processor troubleshooting > Clear TPM. This resets the TPM to factory state. You'll lose BitLocker keys and Windows Hello data, so back those up first.
Update TPM driver
Open Device Manager, expand Security devices. Right-click Trusted Platform Module 2.0, hit Update driver > Browse my computer > Let me pick > choose version 10.0.19041.1 or later. If that fails, download the driver from your motherboard vendor's site — don't rely on Windows Update for this.
Reset BIOS/EFI
Enter BIOS (F2/F10/Del during boot), load optimized defaults, save, and reboot. Also check if TPM is still enabled — sometimes BIOS updates silently disable it. On Dell systems it's under Security > TPM 2.0 Security. On HP it's under Advanced > TPM State.

Alternative fixes if the above doesn't work

Troubleshoot TPM using PowerShell
Run as admin:
```
Get-Tpm
```
Check if TPM is ready. If it shows False, run
```
Clear-Tpm
```
— but only if you're okay losing keys.
Use the TPM Management Console
Press Win+R, type
```
tpm.msc
```
. If it says "TPM is not detectable" or "TPM is off", then the hardware is really the issue. Try reseating the TPM module on your motherboard — some desktops have a removable TPM header that can come loose.
Flush BIOS CMOS
Power down, unplug the power cord, remove the CMOS battery for 30 seconds, put it back, and reboot. This forces a full BIOS reset that often clears corrupt TBM blobs.

Prevention tip

Don't skip TPM driver updates. Most TPM encoding errors come from mixing old drivers with new firmware. Set Windows Update to automatically install driver updates. And before a BIOS update, always clear TPM first — that alone avoids 80% of these errors.

On a Lenovo ThinkPad X1 Carbon Gen 9, I saw this error after a BIOS update failed midway. Clearing TPM from BIOS (not Windows) fixed it. If your TPM is soldered on, clearing from BIOS is safer.

That's it. No voodoo. Clear TPM, update driver, reset BIOS. If none of that works, the TPM chip might be physically dead — rare, but happens on older hardware after repeated power surges.