Fix Blue Screen Errors on Windows 11 (BSOD)

Pull out your phone and photograph the blue screen before the machine reboots. The all-caps text near the bottom — IRQL_NOT_LESS_OR_EQUAL, MEMORY_MANAGEMENT, CRITICAL_PROCESS_DIED, whatever yours says — is the STOP code. That English name matters way more than the hex code underneath it.

Three calls in one afternoon last week. All blue screens. All Windows 11. A freelance translator crashing every 45 minutes — IRQL_NOT_LESS_OR_EQUAL. A shared workstation stuck in a boot loop — CRITICAL_PROCESS_DIED before login. A guy whose Photoshop specifically triggered SYSTEM_SERVICE_EXCEPTION on large PSD files. All three had installed the same KB5058405 cumulative update the night before. Rolled it back on each machine. All three stabilized. Forty minutes total including hold time waiting for the second client to answer.

People see that sad face on a blue background and assume their computer is dying. Almost never true. Microsoft’s own Hardware Dev Center puts the number at 70% of BSOD errors being caused by third-party drivers. Not hardware. Software. A driver did something dumb, Windows crashed deliberately to protect your files, and undoing whatever the driver did fixes it.

The STOP codes I see most often, roughly by frequency: IRQL_NOT_LESS_OR_EQUAL — a driver touched memory it shouldn’t have, almost always network adapter or GPU driver, probably accounts for a quarter of all BSOD tickets I close. MEMORY_MANAGEMENT — could be dying RAM or could be a driver leaking memory; a customer had already ordered replacement DDR4 before calling us, turned out his Realtek audio driver was the issue, free fix. CRITICAL_PROCESS_DIED — a core Windows process crashed, usually file corruption, though twice this year I traced it to antivirus (our CRITICAL_PROCESS_DIED guide covers the full diagnostic). SYSTEM_SERVICE_EXCEPTION — GPU drivers cause this one more than anything else. SYSTEM_THREAD_EXCEPTION_NOT_HANDLED — same story, a driver (usually graphics) threw an exception Windows couldn’t catch, and the .sys filename on the screen names which one. WHEA_UNCORRECTABLE_ERROR — hardware-level, the CPU or chipset reported something it couldn’t self-correct, could be overheating or genuinely failing silicon. CRITICAL_STRUCTURE_CORRUPTION — kernel data got corrupted, could be a buggy driver, bad RAM, unstable overclock, or Intel 13th/14th gen CPU degradation.

Reading the Crash Dumps

Windows logs every crash to C:\Windows\Minidump\ — small .dmp files that record what was happening at the exact moment everything went wrong. Download BlueScreenView by NirSoft — it’s free, about 80KB, no installer. Extract it, double-click, it finds your crash dumps automatically.

The “Caused By Driver” column is where you look. If nvlddmkm.sys shows up across three different crashes — that’s NVIDIA’s display driver. Rt640x64.sys is Realtek’s network adapter. tcpip.sys is Windows networking. ntfs.sys is the file system driver and usually means a disk problem rather than a driver bug. Google the .sys filename if you don’t recognize it, first result tells you what owns that file.

If BlueScreenView specifically shows nvlddmkm.sys crashing during sleep or wake, that’s a DRIVER_POWER_STATE_FAILURE — needs DDU clean install plus specific power settings, different from a regular driver BSOD. If it crashes specifically during gaming or under load and the stop code says DPC_WATCHDOG_VIOLATION, that’s a DPC timing issue — different fix path involving storage controllers and SSD firmware. If your BSODs are causing repeated random restarts and you never see the STOP code because the reboot is too fast, that guide covers disabling automatic restart so the screen stays up long enough to read.

The Driver

Once you know which .sys file is crashing, open Device Manager (right-click Start). Scroll through looking for yellow warning triangles — those are devices where Windows already knows the driver is busted. Right-click the device, Properties, Driver tab. If the crashes started right after a driver update, the Roll Back Driver button reverts to whatever was working before.

If you need a newer version, do not use the “Search automatically for drivers” button in Device Manager. Microsoft’s catalog is perpetually months behind what hardware companies actually ship. Go to the manufacturer’s site: nvidia.com/drivers for NVIDIA, amd.com/support for AMD, your laptop manufacturer’s support page (Dell, HP, Lenovo, ASUS) for everything else. For Realtek specifically, the laptop OEM’s driver is usually better than what Realtek’s own website provides — the OEM version is tested against your specific model.

For GPU drivers — the single biggest BSOD source for anyone who games — the fix is DDU (Display Driver Uninstaller). Boot into Safe Mode, run DDU, let it scorched-earth the old driver including registry entries and stray DLLs. Then reinstall from scratch. A customer had a 4070 Ti that exclusively crashed during one specific game — every other game was fine. Turned out GeForce Experience had botched a driver update, leaving half the files from the new version and half from the old. DDU wipe, clean install of the exact same version from NVIDIA’s site, problem gone. The installation process itself was broken, not the driver version.

System File Repair

Not every BSOD is a driver’s fault. Windows has hundreds of protected system files and any of them can get corrupted — power cuts during updates, malware that deliberately modifies system components, a bad sector on the SSD hitting the wrong file.

Open Terminal as admin. Run sfc /scannow — ten minutes, scans every protected file against factory originals and replaces anything corrupted. If SFC says it found problems it couldn’t fix, the backup copies in WinSxS are also damaged. Run DISM /Online /Cleanup-Image /RestoreHealth — this takes 15-30 minutes and downloads pristine copies from Microsoft’s servers. Then run sfc /scannow again. DISM gives SFC clean source material so the second pass actually works. Our SFC guide covers reading CBS.log results and handling all four possible SFC outcomes.

I don’t even bother testing SFC alone on machines showing CRITICAL_PROCESS_DIED anymore — I just run the DISM-then-SFC pair every time because that STOP code turns out to be file corruption nine out of ten.

RAM and Updates

When your STOP codes change every crash — MEMORY_MANAGEMENT one day, IRQL_NOT_LESS_OR_EQUAL the next, KERNEL_DATA_INPAGE_ERROR after that — bad RAM is likely. Failing memory doesn’t produce one consistent error because different bits fail at different addresses. Windows Memory Diagnostic catches obvious dead-stick failures but misses subtle faults. MemTest86 is the real test — download it, put it on a USB drive, boot from USB, let it run at least two full passes. Each pass takes 45-60 minutes. I’ve found sticks that didn’t show errors until pass 3. Found errors? Pull one stick, test with the other, swap. DDR4 is $15-30 on Amazon, DDR5 runs $30-50. If it’s KERNEL_DATA_INPAGE_ERROR specifically and repeatedly, that usually points to a failing storage drive rather than RAM — our kernel data inpage error guide covers the breakdown.

On the Windows Update front: if your BSODs started within 24-48 hours of seeing “Updating… don’t turn off your PC,” the update is the cause. Check Settings, Windows Update, Update history for what installed recently. Uninstall the matching KB, restart. Block it from reinstalling with Microsoft’s “Show or Hide Updates” tool (wushowhide.diagcab). The 24H2 rollout saw a 340% spike in BSOD reports during its first two weeks. Can’t boot into Windows at all? Force three consecutive failed boots by power-button killing the machine mid-boot to trigger Automatic Repair — from there, Advanced Options, Uninstall Updates. If the machine gets stuck in an automatic repair loop instead of giving you options, you have to break out of that first. Our Windows Update stuck guide covers the full procedure. If you end up doing a clean install and hit an activation error afterward, that’s a separate fix. And if the same bad update also broke your Start menu or Bluetooth, those guides have the specific fixes. If your machine freezes instead of blue-screening, the diagnostic flow is different even though some causes overlap, and if you’ve been through everything here and still crash, send us the Minidump folder on WhatsApp — we decode the .sys filenames and tell you exactly what’s failing in about twenty minutes.