How to fix a Windows Blue Screen of Death (BSOD)
Find out why you got a BSOD and how to stop it.
Few things are more frustrating. You’re in the middle of working on a project, reaching a major milestone in a game or maybe just booting up your Windows 10 computer and, just like that, the entire OS crashes and presents you with a Blue Screen of Death, usually for no immediately apparent reason.
In Windows-speak, the term “Blue Screen of Death” is usually abbreviated as BSOD. It describes an error of some kind that hits the operating system hard enough that it’s forced to quit. Microsoft itself labels such errors with “stopcodes.” Thus these errors may also be generically named “stop errors.” There’s an example that shows what a BSOD sometimes looks like above.
Understanding the BSOD screen
The screen starts with an old-fashioned unhappy face emoticon “:( “(a colon, followed by an open parenthesis). Next, you see a brief explanation that
“Your PC ran into a problem and needs to restart.” Windows writes one or more log files when a stop error occurs, so you see language about “collecting some error info” and a counter that keeps track while it’s writing that data (shows as “20% complete) above.
Microsoft provides a scannable QR code in modern BSODs (lower left) that you can scan with a smartphone and look up that way. The message also provides a lookup URL for stopcodes, where you can enter a numeric stopcode (and where you’ll see most common stopcodes, including the one shown above). The most common stop codes include: - CRITICAL_PROCESS_DIED - SYSTEM_THREAD_ EXCEPTION_NOT_HANDLED - IRQL_NOT_LESS_OR_EQUAL - VIDEO_TDR_TIMEOUT_ DETECTED - PAGE_FAULT_IN_NONPAGED_ AREA - SYSTEM_SERVICE_EXCEPTION - DPC_WATCHDOG_VIOLATION
You can also download the
Microsoft Error Lookup Tool (current version: Err_6.4.5.exe) to look up numeric error codes at a command prompt or in PowerShell, if you prefer.
In Windows 10, BSODs aren’t always blue
Before Windows 8 came along in October 2012, BSODs always appeared on dark blue screens. These were chock-full of text and instructions, and were hard to follow. With Windows 8, Microsoft switched to a kinder, gentler format. They also whittled down the information that appears on screen. In fact, the background colour in Windows 10 is sometimes green, which is why you may see some of them called GSODs (“Green Screens of Death”).
Making sense of BSOD data
Though nobody wants to see a BSOD on a Windows PC, they do occur from time to time. In
the vast majority of cases, the PC will restart itself automatically after an error log, called a crash dump or a dump file (extension . dmp) is created. By default, Windows 10 stores dump files in one of two locations.
You can manage crash dumps through Advanced System Settings in Windows 10 (type “Advanced System Settings” into the search box, then click “Settings” in the Startup and Recovery pane). You can also choose to toggle “Automatic restart” to off here, if you would prefer that any future BSODs stay on the screen until you get a chance to see them and write down (or take pic of) any relevant data.
If you select “Small memory dump” as the option for saving crash dumps, such files show up as Minidump.dmp files. For all other selections, the crash dump is named Memory.dmp. Crash dumps get written to the %SystemRoot% folder, which usually expands to C:\Windows. By design, small memory dump files are limited to 256KB in size. Other memory dumps will vary in size up to the size of memory on the PC where the dump is collected. Thus, on a PC with 16 GB of RAM, a Complete memory dump file will always be 16 GB in size (and other dump files, except for the small memory dumps, can be as large as 16 GB, but will often be smaller).
Examining a crash dump file can be helpful when troubleshooting related causes. That said, many users simply search on the stopcode and/or the numeric error code when seeking remediation advice. (Note that Microsoft calls that numeric code a “bug check code” or “bug check string.”
What to do when troubleshooting a BSOD
The immediate tendency following a BSOD is to get right into fix-it mode, start looking things up, and attempting repairs. Not so fast! Microsoft explains the entire troubleshooting process in its “Troubleshoot blue screen errors” tutorial. While you can – and probably should – read the Microsoft advice in its entirety, here’s a summary of key recommendations:
1. Shut down the Windows PC that experienced the BSOD
2. Disconnect all USB-attached devices except for mouse and keyboard (or wireless dongles).
3. Reboot your system into safe mode from the Windows Recovery Environment (WinRE)
4. If you recently installed new software, uninstall that software.
5. If you recently installed a new device driver (or your BSOD info points to a driver or device), uninstall or roll back that driver (if you don’t really need the device you can disable it temporarily instead)
6. Restart the PC, and see if the BSOD recurs. If not, you’ve probably isolated the cause and can start researching some kind of fix.
7. If the BSOD recurs despite the items taken out of the picture by removing, disabling or uninstalling them, whatever’s still left in the picture remains problematic. At this point you want to reboot into safe mode once again, and open an administrative command prompt or PowerShell session. From the command line, enter these commands, one at a time:
1. DISM /Online /Cleanupimage /Restorehealth
2. SFC /scannow
The first of these two commands finds and replaces any damaged operating system components in the side-by-side filestore (aka WinSxS). The second of these commands runs the System File Checker (SFC) and will repair any damaged files it finds.
Note that if SFC finds and fixes anything, you should run the command until it comes back with a clean bill of health (in some cases, I’ve had to run it two or three times before it came back clean). Note further that running either or both of these commands can take some time to complete, especially if one or both find items in need of fixing.
“BSOD describes an error of some kind that hits the operating system hard enough that it’s forced to quit. Microsoft itself labels such errors with stopcodes.”