The 0x0000009F error, also known as DRIVER_POWER_STATE_FAILURE, occurs in Windows 11 when a device driver enters an invalid or inconsistent power state. This issue commonly triggers a Blue Screen of Death (BSOD), causing the system to crash and reboot unexpectedly. Commonly, this happens when entering or waking from sleep or hibernation modes. Fortunately, there are several effective solutions available to resolve this issue.

Method 1: Update or Roll Back Device Drivers

Since the DRIVER_POWER_STATE_FAILURE error primarily relates to driver issues, updating or reverting device drivers often resolves the problem.

Step 1: Press Win + X and select Device Manager from the menu.

Step 2: Locate the device suspected of causing the issue, usually a USB Wi-Fi adapter or external USB storage device. Right-click the device and select Update driver.

Step 3: Choose the option Search automatically for drivers and follow the prompts to complete the update.

Step 4: If the issue began after a recent driver update, consider rolling back the driver instead. Right-click on the device and select Properties.

Step 5: go to the Driver tab, and click Roll Back Driver. Restart your system after making these changes to see if the issue persists.

Method 2: Adjust Power Management Settings

Incorrect power management settings can cause devices to enter incompatible power states, triggering error 0x0000009F.

Step 1: Open Device Manager by pressing Win + X and selecting it from the menu.

Step 2: Expand the category containing the problematic device (e.g., Network adapters). Right-click the device, select Properties.

Step 3: Navigate to the Power Management tab. Uncheck the box labeled "Allow the computer to turn off this device to save power" and click OK.

Step 4: Additionally, disable Fast Startup, which can sometimes cause power-state conflicts. Open the Control Panel and go to Hardware and Sound.

Step 5: Go to Power Options and then click Choose what the power buttons do.

Step 6: Then click Change settings that are currently unavailable and uncheck "Turn on fast startup" before saving your changes. Restart your computer to apply these changes.

Method 3: Disconnect and Test External USB Devices

External USB devices, particularly storage drives and Wi-Fi adapters, frequently trigger the DRIVER_POWER_STATE_FAILURE error. Disconnecting these devices temporarily can help identify the culprit.

Step 1: Unplug all non-essential USB devices, leaving only essential peripherals like keyboards and mice connected.

Step 2: Restart your Windows 11 machine to see if the error continues. If the error stops occurring, reconnect devices one at a time to pinpoint the problematic hardware.

Once identified, update or replace the device or its driver to resolve the issue permanently.

Method 4: Run DISM and SFC System Repairs

Corrupted system files or damaged Windows components can also cause the 0x0000009F error. Running built-in Windows repair tools can fix these issues.

Step 1: Press Win + S, type cmd, right-click Command Prompt, and select Run as administrator.

Step 2: Run the Deployment Image Servicing and Management (DISM) tool by entering the following command and pressing Enter:

DISM /online /cleanup-image /restorehealth

Wait for the operation to complete (this may take several minutes).

Step 3: Next, run the System File Checker (SFC) tool by typing this command and pressing Enter:

SFC /scannow

Allow the process to finish, then restart your computer. These commands repair corrupted system files and restore Windows stability.

Method 5: Boot into Safe Mode and Remove Problematic Drivers

If the above methods don't resolve the issue, booting into Safe Mode allows you to isolate and uninstall problematic drivers safely.

Step 1: Boot into Safe Mode by following the instructions provided in Microsoft's official support page.

Step 2: Once in Safe Mode, open Device Manager (Win + X > Device Manager), find the recently installed or updated device drivers, right-click them, and select Uninstall device.

After uninstalling, reboot your computer normally. Windows will automatically reinstall default drivers upon reboot, potentially resolving the BSOD issue.

By following these methods, you can effectively resolve the DRIVER_POWER_STATE_FAILURE (error 0x0000009F) in Windows 11. If the issue persists, consider seeking professional technical support to examine hardware components or deeper system diagnostics.