APC_INDEX_MISMATCH Blue Screen Error on Windows 10/11

PC Repair Windows
BSOD System Crash Programming

For many Windows users, a BSOD is the worst that could ever happen to a PC. Unlike application crashes, a BSOD error brings the entire system down, preventing a user to do anything.

However, BSODs should not be feared. As with other errors, they can be fixed. While some solutions call for a simple reboot, others require professional assistance.

In this article, we’ll tackle one frustrating BSOD error that Windows 10/11 users may encounter and share solutions that may fix it.


The APC_INDEX_MISMATCH error message, often accompanied by error codes 0x97503177 or 0x02A7DA8A, generally appears to warn users that no software can run without having to risk of damaging your operating system. Because there is an existing inconsistency in the number of processes that launched, the BSOD screen surfaces.

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Now, you may ask, “What are the causes of APC_INDEX_MISMATCH error on Windows 10/11?” Well, the true cause is yet unknown. But according to Microsoft, it is a kernel internal error that happens on exit from a system call. It could happen when a certain device or system driver has a mismatched call sequence to disable or re-enable APCs. For some affected users, the APC_INDEX_MISMATCH error may also be caused by upgrading from an older Windows 10 version to a later one.

How to Fix APC_INDEX_MISMATCH Error on Windows 10/11

What should you do about APC_INDEX_MISMATCH error on Windows 10/11? Should you let a professional handle the error or simple DIY fixes can do the trick?

If you are having a hard time dealing with this error message, the solutions below might help. We have compiled a collection of fixes that others affected users have tried to resolve the error. We suggest you follow them in the order presented below until you find one that works for your situation.

Solution #1: Update your system to the latest version

If the BSOD error occurred while using your device’s webcam, then the fix should be easy. Simply install and apply any pending Windows update and you should be all set.

There was a time when the APC_INDEX_MISMATCH error was associated with programs that use the webcam. According to reports, Skype encountered an issue after a certain Windows update. Fortunately, it was immediately fixed by Microsoft.

If this is your situation, then upgrading your OS to the most recent version will do the trick. To update Windows, do the following:

  1. Press the Windows + R keys.
  2. Into the text field, input ms-settings:windowsupdate and hit Enter. This will launch the Windows Update menu.
  3. Press the Check for Updates button and follow the on-screen prompts.
  4. Depending on how many updates are pending, your device will restart every now and then.

Solution #2: Install a new driver version of Realtek High Definition

As mentioned, the BSOD error can also be caused by a corrupted or outdated device driver. So, to fix the issue and prevent the system from crashing, some users simply reinstalled the Realtek audio driver.

To install the latest Realtek High-Definition device driver, visit the official website of Realtek. From here, download the most recent audio driver that is compatible with your operating system’s architecture. Once the driver has been successfully downloaded, just follow the on-screen prompts and restart your device. Upon the next startup, check if your device still crashes. If it does, proceed to the next solution.

Solution #3: Use the Base Windows Audio Driver

If you still suspect that your audio driver is the culprit, there is another solution that has helped plenty of users in the same situation. This is very much recommended to users running Dell laptops.

According to the affected users, uninstalling the Realtek audio driver and installing the Windows Base audio driver have caused the BSOD error to stop. Here’s a detailed guide on what to do:

  1. Press the Windows + R keys to launch the Run dialog box.
  2. Into the text field, input devmgmt.msc and hit Enter. This will open the Device Manager window.
  3. Next, scroll down to the Sound, video and game controllers section.
  4. Right-click on the Realtek High-Definition Audio section and click Uninstall Device.
  5. Exit Device Manager.
  6. Now, open the Run dialog box once again by pressing the Windows + R keys.
  7. Into the text field, input appwiz.cpl and hit Enter. This will launch Programs and Features.
  8. Scroll through the list and find Realtek High-Definition Audio Driver. Right-click on it and select Uninstall.
  9. Follow the on-screen prompts to completely remove the Realtek device driver.
  10. Reboot your computer to apply the changes.
  11. At the next startup, open Device Manager again and check if Windows Audio Base Driver is under the Sound, video and game controller section. If it is, check if the error persists. Otherwise, try another solution.

Solution #4: Make sure all device drivers are properly installed

It is possible that the BSOD error appears because a hardware component is not functioning properly due to an incorrectly installed or missing device driver. In this case, it is worth checking the status of all your installed device drivers.

The quickest and easiest way to do so is to use Device Manager. Here’s how:

  1. Press the Windows + R keys to open the Run dialog box.
  2. Into the text field, input devmgmt.msc and hit Enter.
  3. Scroll down the list of device drivers and check if there is any that has a yellow icon. This icon serves as an indicator that the driver has to be updated.
  4. If you see the yellow icon, right-click on it and select Update Driver.
  5. Once the driver has been successfully updated, restart your PC.

Solution #5: Run the BSOD Troubleshooter

In case you don’t know, Microsoft has created a troubleshooter for BSODs. To access and use this, visit the official Microsoft website. Here, you will find a simple wizard that will guide you in the process of troubleshooting BSODs. Most likely, you will be asked when did you first get the BSOD error. Just make sure to provide the appropriate answers to ensure you troubleshoot the problem correctly.

Solution #6: Perform a Clean Install

If the APC_INDEX_MISMATCH BSOD error still occurs, try to perform a clean install. Although this isn’t really ideal as it requires technical knowledge, it’s worth giving a try because it worked for many users.


Like other BSOD errors, dealing with the APC_INDEX_MISMATCH error on Windows 10/11 may be a challenge. However, we hope that the solutions we have enumerated above are of great help. If updating to the latest Windows version doesn’t work, you may try using the online troubleshooter. But if all these solutions seem to difficult for you, we suggest you seek help from a professional Windows technician.

Have you encountered the APC_INDEX_MISMATCH error before? How did you deal with it? We’d love to know! Share your solutions in the comments.

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