CompTIA A+ Core 2 (220-1202)Software TroubleshootingHard
A technician installs a new third-party antivirus suite on a Windows 11 laptop. Immediately after, the system blue-screens with the stop code KERNEL_SECURITY_CHECK_FAILURE on every normal boot attempt, but the laptop boots successfully into Safe Mode. Which of the following is the BEST next step?
- ARoll back the most recent BIOS/UEFI firmware update
- BReplace the laptop's RAM modules
- CBoot into Safe Mode and uninstall the third-party antivirus software
- DRun bootrec /fixmbr from the Windows Recovery Environment
Show answer & explanationAnswer & explanation
Correct answer: C. Boot into Safe Mode and uninstall the third-party antivirus software
Since the BSOD began immediately after installing the third-party antivirus and the system boots fine in Safe Mode (which loads minimal drivers), the antivirus's kernel-level driver is the most likely cause. Uninstalling it in Safe Mode removes the conflicting driver without needing a boot record repair or hardware replacement.
Why the other options are wrong
- A. Rolling back BIOS/UEFI addresses firmware issues, not a software driver conflict tied to the antivirus install.
- B. RAM replacement is unwarranted without hardware failure symptoms like random crashes unrelated to a software install.
- D. bootrec /fixmbr repairs boot record corruption, not a driver conflict causing BSOD.
Driver Conflict BSOD (Third-Party Security Software)
A blue screen caused by a newly installed driver, commonly from security software, that conflicts with the OS kernel; often resolved by uninstalling the software in Safe Mode.
- Safe Mode loads only essential drivers, isolating the faulty one
- Timing correlation with a recent install is a key diagnostic clue
- KERNEL_SECURITY_CHECK_FAILURE often points to a corrupted or conflicting driver
Memory trick: Safe Mode works = the new antivirus driver is the troublemaker