If you are trying to tighten up your security by adding Virtualization-Based Security (aka VBS) to your Windows 11 you might find this error:

Core Isolation  Memory Integrity
Incompatible Drivers WDCSAM64_PREWIN8.SYS

Driver date: 11/29/2017
Driver version: 1.2.0.0

Published name: oem26.inf

Windows 11 Core Issolation incompatible driver wdcsam64_prewin8 sys

This is an old driver that ships with both Windows 10 and Windows 11 and very few people need it.  In fact we have never run into a situation of any machine using WDCSAM64_PREWIN8.SYS .

Fortunately, it is very easy to remove:

  1. RIGHT click on the START button and select WINDOWS TERMINAL (ADMIN)
    • If you are on Windows 10, select POWERSHELL (ADMIN)
  2. You can then list all of the drivers on your computer using pnputil /enum-drivers and find the one with WDCSAM64_PREWIN8.SYS or you can just look at the error message.  In my case the driver that needs to go is OEM26.INF
  3. Uninstall the driver using pnputil /delete-driver oem<XX>.inf

2 Windows 11 Core Issolation uninstall - remove incompatible driver wdcsam64_prewin8 sys

You do NOT need a reboot so you can immediately retry to enable CORE ISOLATION and you should see a prompt to reboot once Core Isolation > Memory Integrity is turned ON.

Windows 11 Core Issolation Reboot Required


21 Comments

Trevor · June 15, 2022 at 9:42 am

Failed to delete driver package: One or more devices are presently installed using the specified INF.

anonymous · June 9, 2022 at 5:14 am

Very thanks, I found a lot of methods to solve this problem but didn’t work. U gave a useful method.

Carlos · April 22, 2022 at 11:00 am

i have 26oem.inf like hw_usbdev.info or Huawei incorporated, i don´t found the driver WDCSAM64_PREWIN8.SYS.

Angel · April 17, 2022 at 5:12 am

Thank you! It was very useful. I had the same problem as in another comment, receiving the “access denied” message while trying to delete the file. That’s strange because I’m the owner of the laptop and am supposed to be the administrator. But tried executing the windows terminal as administrator and could delete the file. In Windows 11, before executing the terminal, choose the option as administrator.

Abrar Fahim Khan · April 4, 2022 at 8:30 am

Mine says Access is denied.

    Anson · May 21, 2022 at 7:12 pm

    Need to open PowerShell as Administrator

Franklin A Gibson · March 31, 2022 at 12:28 pm

thanks Ian Matthews. I’ve been trying to phrase my search phrase just right to find this information for 24 hours! I finally achieved! thank you much for this info.

earl veale (@earlveale) · March 27, 2022 at 5:36 pm

Thank you Ian. Your instructions were very good, and I was able to remove the old, no longer needed, driver.

Shawn W · February 20, 2022 at 6:19 pm

Thank you very much. I had a different incompatible driver (AsIO64.sys, oem45.inf) but the same problem. I tried so many things without success before I tried your technique. Your solution worked perfectly.

    Ian Matthews · February 21, 2022 at 5:45 pm

    Yaaaa! Thanks Shawn

Nihaal · February 12, 2022 at 10:02 am

I deleted every driver that was unnecessary and listed there. After deleting & scanning there are no incompatible drivers, but still I can’t turn on Memory Integrity.

    Ian Matthews · February 21, 2022 at 5:54 pm

    Hi Nihall;

    Did it give you an error message?

      James Alan Heider · May 25, 2022 at 7:18 pm

      That is what I got received back as well.
      what to do now?

Robert Dianella · January 20, 2022 at 6:36 pm

The system won’t let me delete this file. Says it’s in use by one or more devices.

    Ian Matthews · January 29, 2022 at 12:45 pm

    Hi Robert, we responded to your previous comment with the same suggestions we would make here:

    Hi Robert;

    Three things to try:
    1: reboot
    2: reboot in safe mode
    3: uninstall any programs / addins you are not using – many people leave software intalled for old scanners, printers, cameras… and that really expands your attack surface

    Let us know how that goes and thanks for checking in with us.

Christiano · December 5, 2021 at 5:24 am

Many thanks, it’s work to me !

Martin Bligh · November 20, 2021 at 6:45 am

Cannot delete this driver

    robertdianella · January 20, 2022 at 6:33 pm

    I get an error message that says the driver is in use by one or more devices and will not delete.

      Ian Matthews · January 29, 2022 at 12:44 pm

      Hi Robert;

      Three things to try:
      1: reboot
      2: reboot in safe mode
      3: uninstall any programs / addins you are not using – many people leave software intalled for old scanners, printers, cameras… and that really expands your attack surface

      Let us know how that goes and thanks for checking in with us.

        Oliver · February 16, 2022 at 9:01 am

        Im having this issue aswell and I just build this pc and installed the drivers, got any tips?

          Ian Matthews · February 21, 2022 at 5:55 pm

          Hi Olvier;

          Are you receiving an error message?

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