Fix: ERROR_BAD_MCFG_TABLE (Error Code 791)

The ERROR_BAD_MCFG_TABLE Windows system error, with code 791 (0x317), appears when Windows has a problem interacting with a connected device or peripheral. The error message in the Device Manager reads, The resources required for this device conflict with the MCFG table.

Under the Device status section in the General tab, it says, Your computer’s firmware does not include enough information to properly configure and use this device. To use this device contact your computer manufacturer to obtain a firmware or BIOS update.

This usually happens due to issues with the system’s firmware or BIOS, corrupt or incompatible drivers, or misconfigured settings. Before you proceed to the solutions, restart the computer, install all pending Windows updates, and reconnect the affected hardware!

How do I fix ERROR_BAD_MCFG_TABLE in Windows?

1. Reinstall the affected device’s driver

1. Press Windows + X to open the Power User menu, and select Device Manager.
2. Look for any device with a warning sign (yellow exclamation mark) next to its icon, then right-click on it, and select Uninstall device.
3. Tick the checkbox for Attempt to remove the driver for this device, if available, and click on Uninstall.
4. Finally, restart the computer and Windows will install a fresh copy of the driver.

2. Update the driver

1. Press Windows + R to open Run, type devmgmt.msc in the text field, and hit Enter.
2. Locate the affected device, right-click on it, and select Update driver.
3. Click on Search automatically for drivers and wait for Windows to install the best locally available version.
4. Once done, reboot the computer to apply the changes.

Outdated or incompatible drivers are a common reason behind ERROR_BAD_MCFG_TABLE 791 (0x317) The resources required for this device conflict with the MCFG table. To fix things, you must update the drivers!

If Windows can’t find a better version, go to the manufacturer’s official website, locate the new releases, and then manually install the latest driver!

3. Perform a system restore

1. Press Windows + S to open Search, type Create a restore point, and click on the relevant result.
2. Click the System Restore button.
3. Select the Choose a different restore point option, if available, and click Next.
4. Pick the oldest restore point from the list, and click Next.
5. Verify the details, click on Finish, and confirm the change.
6. Wait for the system restore to complete. It typically takes 15-45 minutes.

If the oldest restore point is from a long time ago, choose any other restore point created before you first encountered Error Code 791 (ERROR_BAD_MCFG_TABLE)

4. Reset the BIOS

1. Turn off the PC, then power it on, and as soon as the display lights up, repeatedly hit the F1, F2, F10, F12, Esc, or Del key, depending on the system manufacturer, to access the BIOS.
2. Now, look for a Reset, Default, or Load Defaults option, and click on it.
3. Choose the appropriate response to confirm the BIOS reset.
4. Once done, exit the BIOS, boot Windows, and check for improvements.

When you are getting ERROR_BAD_MCFG_TABLE with PCI Express Root and the ports fail to work, resetting the BIOS will do the trick. That’s because the error could be arising due to misconfigured BIOS/UEFI settings!

5. Update the BIOS

When nothing else works, the last option is to update the BIOS. In the past, manufacturers have acknowledged that The resources required for this device conflict with the MCFG table was triggered due to a bug in the BIOS and the later versions included a patch for it.

If an update is not available, reach out to the manufacturer’s support team and ask for a resolution since they provide the MCFG table. Until you fix that, PCI Express devices will continue to malfunction or not show up at all.

Before you leave, find out the common Windows errors and their expert solutions and take suitable measures to prevent such issues from reappearing!

For any queries or to share what worked for you, drop a comment below.