How to Fix the APC_INDEX_MISMATCH in Windows 10

Learn how to fix the APC_INDEX_MISMATCH error when the computer crashes.

APC_INDEX_MISMATCH errors are BSOD errors in Windows 10 and may prevent your computer from starting completely. Although the error is not common, you can use some simple troubleshooting methods to fix it.

1. Check Your Computer’s Drivers

Most Windows 10 blue screen errors, including APC_INDEX_MISMATCH errors, are caused by faulty or outdated drivers. To find out the cause, look up the file name on the error screen, and then google to find the relevant driver.

For example, if the crash lists “RtlUpd64.exe” as the cause of the error, the Realtek HD Audio Driver will not work properly. In this case, you need to update or uninstall the driver to see if the error can be resolved.

How to Update a Driver Using Device Manager

How to Fix the APC_INDEX_MISMATCH in Windows 10

Press Windows Key + R to open the Run application. Type devmgmt.msc in the text box and press Enter to open the Device Manager.
In the Device Manager window, scroll down and expand the Sound, video and game controllers section.
Right-click on Realtek High Definition Audio(SST) and select Update driver.
In the update prompt, click on Search automatically for drivers.
Windows will automatically download the latest drivers and install them.

How to Uninstall a Driver

Press Windows Key + R to open the Run application. Type devmgmt.msc in the text box and press Enter to open the Device Manager.
Now, scroll down and expand the section related to the driver you want to uninstall.
Right-click on the driver and select Uninstall device.
In the uninstallation prompt, be sure the check the Delete the driver software for this device option.
Click on Uninstall and after the process is complete, reboot your computer.

2. Boot Your Computer Into Safe Mode

Another major cause of APC_INDEX_MISMATCH errors is that third-party applications may interfere with the functionality of your computer.

The best way to diagnose this problem is to check if the error persists after disabling third-party applications. This can be done by restarting the computer cleanly or booting in safe mode.

Although clean restart is not an official option in Windows, safe mode is one of them and only loads minimal functions and programs.

How to Boot in Safe Mode

Click on the Start button and open Settings.
On the Settings dashboard, click on Update & Security.
On the navigation bar on the left, click on Recovery.
Scroll down and under Advanced startup, click on Restart now.
Your computer will boot into the Choose an option screen.
Here, select Troubleshoot > Advanced options > Startup settings > Restart.
Once your computer reboots, you will see a list of options. On this screen, press F4.
Your computer will reboot into Safe Mode.

Now try to use your computer as usual and see if the APC_INDEX_MISMATCH error persists. If it is not, a third-party driver or software may be causing the error.

Uninstall all recently installed applications or download a different version.

3. Update Windows to the Latest Version

Microsoft regularly releases new updates for Windows, and these updates also include bug fixes. Therefore, you need to update your PC to the latest version.

If you are using an older version of Windows with many unresolved errors, the APC_INDEX_MISMATCH error will often appear. Fortunately, Windows will automatically update itself, but for sure, you can manually check for the latest updates.

In addition, Windows Update is notorious for getting stuck.

How to Check for Windows Updates

Click on the Start button and click on Settings.
In the Settings dashboard, click on Update & Security.
On the navigation bar on the left, click Windows Update.
Click on Check for updates.
Windows will check the web for the latest updates.
If there are any updates available, click on Download and install.
Windows will automatically install the updates.

On the other hand, newer updates may cause some unforeseen errors, such as: B. APC_INDEX_MISMATCH error. Although rare, there have been some updates in the past that have caused similar errors.

The best way to determine this error is to check if the error occurred after updating the computer. If so, it is likely that a new update has caused this situation. In this case, it is best to uninstall the latest update and wait for another stable update.

How to Uninstall Recent Updates

Click on Start and go to Settings.
In the Settings menu, select Update & Security.
Click on Windows Update on the navigation bar.
Click on View update history, and in the next window, click Uninstall updates.
Your PC will uninstall all recently installed Windows updates.

4. Reset Your Computer

This method should be used as a last resort, as it will delete all your personal settings, files and applications. If none of the above methods work, the only solution is to reset your PC or use System Restore (if you have created a restore point).

How to Reset Your PC

Click on the Start button and go to Settings.
In the Settings dashboard, click on Update & Security.
On the navigation bar, click Recovery.
Under Reset this PC, click on Get Started.

You can keep files and applications in the reset wizard. This option only reinstalls Windows, but is unlikely to work, because it is likely that an application or other file caused the error in the first place.

You can also completely wipe your PC and reinstall Windows.

In addition to resetting this PC, you can also use Windows System Restore to restore your computer to an earlier state. However, this only works if you have previously enabled System Restore and Windows created a restore point.

How to Restore Windows to an Earlier State

In the Start menu search bar, type Recovery.
From the search results, click on the Recovery Control Panel setting.
In the next window, click on Open System Restore. You will need administrator privileges to do so.
If you have created a System Restore point, the wizard will prompt you to choose the restore point.
Click Finish.

APC_INDEX_MISMATCH Crash Resolved

You can use the steps above to resolve the APC_INDEX_MISMATCH BSOD. In addition, these steps can also be used to resolve other common blue screen errors, as most of them are caused by similar issues.