CrowdStrike Falcon BSOD 0x50: Quick Fix Guide

Quick answer: Boot into Safe Mode, rename C:\Windows\System32\drivers\CrowdStrike\CsAgent.sys to CsAgent.sys.old, reboot, then roll back the Falcon sensor to the previous version or uninstall it entirely.

I had a client last month—a small accounting firm—where every single workstation blue-screened within an hour of the CrowdStrike sensor auto-update. The screen said PAGE_FAULT_IN_NONPAGED_AREA with stop code 0x50. That's a classic kernel memory access violation, and when it happens right after a Falcon update, the driver is almost always the culprit. CrowdStrike pushes sensor updates frequently, and occasionally a build ships with a bug that tries to touch memory it shouldn't. Windows doesn't tolerate that, so it crashes. The good news: you can fix it without reinstalling Windows.

What causes this specific 0x50 crash?

Stop code 0x50 means a driver referenced invalid memory. CrowdStrike's Falcon sensor runs at the kernel level—it has to, to monitor process activity—so any bug in its memory handling takes down the whole system. I've seen this happen with sensor versions 6.45 and 7.02 on Windows 10 22H2 and Windows 11 23H2, usually on machines with older chipset drivers or certain antivirus leftovers. The update itself isn't malicious, but it conflicts with something already loaded. The fix is to get rid of the bad driver long enough to roll back.

Step-by-step fix

Force a hard shutdown. Hold the power button for 10 seconds. You need to interrupt the boot loop.
Boot into Safe Mode. Power on and immediately hold F8 (or Shift+F8) until you see the recovery menu. Choose Troubleshoot > Advanced Options > Startup Settings > Restart, then press 4 for Safe Mode. If F8 doesn't work, use a Windows install USB and choose Repair your computer.
Open an elevated Command Prompt. In Safe Mode, right-click Start, pick Terminal (Admin) or Command Prompt (Admin).
Rename the Falcon driver folder. Run these commands one at a time:
```
cd C:\Windows\System32\drivers
ren CrowdStrike CrowdStrike.old
```
If you get an access denied error, take ownership first:
```
takeown /f CrowdStrike /r /d y
icacls CrowdStrike /grant administrators:F /t
```
Then retry the rename.
Disable the CrowdStrike service. Still in Command Prompt:
```
sc config csagent start= disabled
sc config csdevicecontrol start= disabled
```
That stops Windows from trying to load the broken driver on next boot.
Reboot normally. You should get a clean desktop. If Windows still crashes, repeat Safe Mode and also rename C:\Windows\System32\drivers\CrowdStrike\CsDeviceControl.sys to .old.
Roll back the Falcon sensor. Once you're back in Windows, open an admin PowerShell and run:
```
Get-WmiObject -Class Win32_Product | Where-Object { $_.Name -like "*CrowdStrike*" } | Select-Object Name, Version
```
If you have the previous installer (usually a .exe from your CrowdStrike console), run it and choose Repair or Reinstall. Otherwise, uninstall the sensor completely via Programs and Features, then install the latest version from the CrowdStrike Falcon console—but first check the release notes for known 0x50 issues.
Clean up. Delete the CrowdStrike.old folder after you've confirmed stability. Re-enable the services if you reinstalled:
```
sc config csagent start= auto
sc config csdevicecontrol start= auto
```

If that doesn't work

Sometimes the driver folder rename isn't enough because CrowdStrike also drops a kernel filter driver elsewhere. Try these in order:

Use System Restore. Boot into Safe Mode, open rstrui.exe, and roll back to a restore point from before the update. This is the fastest fix if you have a recent point.
Uninstall via Windows Recovery Environment. If you can't even get into Safe Mode, boot from a Windows USB, choose Repair > Troubleshoot > Command Prompt, and manually delete the driver folder. Then run dism /image:D:\ /remove-driver /driver:CrowdStrike\CsAgent.inf (replace D: with your Windows drive).
Check for conflicting software. I've seen this crash when CrowdStrike runs alongside SentinelOne or older Symantec Endpoint Protection remnants. Remove any other security agents before reinstalling Falcon.
Update your chipset and storage drivers. On a few Dell OptiPlex 7090 machines, a stale Intel RST driver caused the same 0x50 after a Falcon update. Grab the latest from Dell's support site.

Prevention tip

Don't let CrowdStrike auto-update during business hours. In the Falcon console, set update policies to a maintenance window and test new sensor versions on a small pilot group first. I always tell clients to keep one spare machine on the previous version just in case. Also, make sure System Restore is enabled on every workstation—that's saved me more times than I can count.