Windows update blocks the PTE


The TOVA Company has discovered that a recent update to Windows 10 and 11 (KB5012170) is causing computers not to be able to boot the Modern Precision Test Environment (PTE).


This problem affects all T.O.V.A. customers with Windows 10 or 11 computers using the Modern (UEFI-based) PTE. If you’re not sure if that includes your computer, here’s how to check:

First, check that you are running Windows 10 or 11:

    1. Click the Start button.
    2. Type winver and press ‘Enter’.
    3. An About Windows window should appear. If it says ‘Windows 10’ or ‘Windows 11’, this update will eventually be installed on your computer, if it isn’t already.

Next, check if you are using the Modern PTE:

  1. Run the T.O.V.A. application.
  2. In the main T.O.V.A. window, click ‘Preferences’ and then ‘Session launch’.
  3. If ‘External Audio/Video (EAV)’ is selected, you are not using the PTE: STOP HERE! This problem does not affect your system.
  4. Otherwise, click ‘Cancel’ in the Preferences window and then click ‘Help’ in the main T.O.V.A. window.
  5. In the Help window, look for the 'PTE Version'.
    • If PTE Version starts with B or 9, you are using the Legacy (BIOS) PTE: This problem does not affect your system.
    • If PTE Version is None recorded and this is a new install, we recommend you use the External Audio/Video (EAV) setup until we have a fix for this issue.
    • If PTE Version starts with U, then you are using the Modern PTE, and your system will be impacted by this update, if it isn’t already.
pte version screenshot


If the Modern PTE is still booting on your system, then KB5012170 has not yet been in installed. If this is the case, you can prevent the update from being installed in two ways:

  • Disconnect your T.O.V.A. computer from the internet – This is a secure way to prevent the Windows update from occurring. Once we’ve fixed the issue, you can reconnect your computer to the internet, download the T.O.V.A. update, and your computer will automatically update Windows 10/11.
  • Suspend Windows 10/11 updates until this issue is resolved – WARNING: Suspending updates can introduce security vulnerabilities.
    1. Click the Start button.
    2. Type service and select ‘Services’.
    3. Scroll down and double-click ‘Windows Update’.
    4. If Service status is Running, click ‘Stop’.
    5. Set ‘Startup type’ to ‘Disabled’ then click ‘OK’.
    6. Restart your computer. 

Warning: Windows might override this setting or could have already started this update, in which case you’ll still need to disable Secure Boot or switch to the EAV hardware setup.


Unfortunately, if KB5012170 has already been installed, uninstalling it will not fix the problem.

While we are working on a fix, you can choose one of the following alternatives to restore functionality to the Modern PTE.

Alternative 1: Switch to the T.O.V.A. External Audio/Video setup

Switch your T.O.V.A. installation to the the EAV setup. This requires an external monitor, but is a fast and secure way to administer the T.O.V.A. that does not require rebooting your computer into the PTE.

Alternative 2: Disable Secure Boot

Disabling Secure Boot will immediately fix the problem and allow you to boot into the PTE, but introduces a security vulnerability. You can keep your T.O.V.A. system secure by disconnecting it from the internet; internet connectivity is helpful to the T.O.V.A. but is not required.

If you do not have IT staff to assist you, you can send a Tech Support request for assistance. If nothing else, take a photo or print out these directions before starting.

bit locker screenshot
  1. Check for BitLocker: Bring up the Windows Start menu, start to type bitlocker, and choose ‘Manage BitLocker’:
    • If BitLocker is on, STOP HERE and send a Tech Support request for “special BitLocker instructions“.
    • If Bitlocker is off or does not appear, and you are not using other drive encryption, proceed to Step 2.
  2. These instructions make changes to low-level system settings. Make sure that your computer is backed up before continuing.
  3. Enter your UEFI Firmware Settings (aka BIOS setup). Here’s how:
    1. Bring up the Start menu, type bios, and choose ‘Change advanced startup options’.
    2. Under Advanced startup, choose ‘Restart now’.
    3. In the blue Boot Options menu, choose ‘Troubleshoot’ > ‘Advanced options’ > ‘UEFI Firmware Settings’ > ‘Restart’.
  4. Systems vary a lot from this point, but you need to find the setting for ‘Secure Boot’. This will be located in your “BIOS Setup” under “Security” or “Boot”. Pay attention to the directions on screen for how to navigate and change settings.
  5. Once you find ‘Secure Boot’, disable it.
  6. Find the option to Save and exit your UEFI Firmware Settings/BIOS setup. Your system will reboot and Windows will start up.
  7. Try launching a PTE session.
    1. Run the T.O.V.A. and click ‘Help’ > ‘Test the PTE’ > ‘OK’. The PTE should now boot normally.
    2. Exit the PTE. The computer should boot back to Windows normally.

* On SOME systems, you can repeat Steps 3 – 6, but this time enable Secure Boot, and the PTE will still boot normally. This does NOT work on all systems, however. (NOTE: If there is an option to enable Microsoft and 3rd-Party certificates, please enable both.)

We deeply apologize for this problem. We will be sure to announce the fix as soon as it becomes available.

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