Quick Answer
Disable Fast Startup and update your chipset drivers. If that doesn't stop the reboots, test or replace the PSU before touching anything else.
Why This Happens
Event ID 41 (Kernel-Power) is logged when Windows starts up after an unexpected shutdown—power loss, hard reset, or a crash that prevented a clean shutdown. The system didn't get a chance to write its shutdown logs, so it just says "The system has rebooted without cleanly shutting down first." That's it.
I've seen this error on hundreds of machines over the last 14 years. The culprit is almost always one of three things, in this order: a failing power supply, a driver that's sending the system into an improper power state, or a motherboard firmware bug. Don't bother with registry tweaks or "fix tools" that claim to repair kernel power events—they're snake oil. The fix is hardware or driver level, not software registry level.
The Fix
- Disable Fast Startup (Windows 10/11) — This is the first thing I do because it's free and takes 30 seconds. Fast Startup is a hybrid shutdown that can leave devices in a weird state, causing wake-from-sleep reboots that trigger Event ID 41. Go to
Control Panel > Power Options > Choose what the power buttons do, click "Change settings that are currently unavailable," then uncheck "Turn on fast startup." Restart. - Update chipset and storage drivers — Go to your motherboard or laptop manufacturer's site and grab the latest chipset, SATA/AHCI, and NVMe drivers. Don't rely on Windows Update; it's often months behind. For Intel systems, that's the Intel Chipset INF update. For AMD, it's the AM4/AM5 chipset driver package.
- Test the power supply — If the reboots continue after disabling Fast Startup, stop troubleshooting software and test the PSU. A $10 power supply tester from Amazon will tell you if the rails are within spec. Better: swap in a known-good PSU from another machine. The Event ID 41 often appears right when the PSU can't deliver enough power under load—like when gaming or running a stress test.
If That Doesn't Work
Try these only after the steps above fail—they're less common but I've seen them fix stubborn cases.
Check RAM with MemTest86
Bad RAM can cause kernel crashes that look like power loss. Boot MemTest86 from a USB drive and let it run for at least 4 passes. If you see any red errors, replace the stick. Don't skip this; I've seen Event 41 caused by a single bad memory module.
Update motherboard BIOS/UEFI
Motherboard makers sometimes fix power state bugs in firmware updates. Check the support page for your exact board. For example, ASUS released a BIOS update in 2023 that fixed Event 41 issues on X670 boards with Ryzen 7000 series. Back up your settings first.
Change PCIe Power Management
Some GPUs and NVMe drives misbehave with the default power saving. In Windows, go to Device Manager > PCI Express Root Port and under Power Management, uncheck "Allow the computer to turn off this device to save power." Do this for any port that has your GPU or NVMe drive attached. Also set the GPU's power management mode to "Prefer Maximum Performance" in NVIDIA Control Panel or AMD Software.
Prevention Tips
Once you've stopped the reboots, do these to keep Event ID 41 from coming back:
- Use a UPS — If you're in an area with dirty power or brownouts, a decent UPS cleans the sine wave and prevents sudden shutdowns. I use APC or CyberPower, nothing fancy.
- Keep your drivers lean — Don't install every optional driver from manufacturer sites. Only grab chipset, storage, and network. Extra utilities like RGB controllers can cause power state issues.
- Set a static Windows power plan — Use "High Performance" or "Ultimate Performance" if you're on a desktop. Laptops need Balanced, but on desktops, these plans prevent the CPU from dropping into low power states that can trigger instability.
And if you're on a system you built yourself, double-check all power cables—especially the CPU 8-pin. A loose connection will cause random shutdowns that log Event 41 every single time.