How to fix Stop Code: SYSTEM_THREAD_EXCEPTION_NOT_HANDLED(0x7E) What failed: FLTMGR_SYS after running the Windows 11, 24h2 version update on a Windows 11, 23H2 Computer?

Question

I’m having a persistent issue upgrading several Dell PCs from Windows 11 23H2 to 24H2. The upgrade consistently fails during the first reboot with a BSOD: SYSTEM_THREAD_EXCEPTION_NOT_HANDLED (0x7E) and What failed: FLTMGR.sys. In some attempts I also saw APC_INDEX_MISMATCH (NTFS.sys), but the primary repeating error is the FLTMGR.sys crash.

I have already gone through extensive troubleshooting. I removed or disabled all non-Microsoft filesystem filter drivers (Elastic, SentinelOne, Dell SupportAssist OS Recovery drivers such as CmgPassThrough and CmgShieldFFE). I verified via fltmc filters that only Microsoft filters remain. I also ran CHKDSK with /f /r, SFC, and DISM /RestoreHealth with no reported integrity violations. Storage drivers, BIOS, and firmware have been updated through Dell Command Update. Despite this, both Windows Update and manual ISO upgrades to 24H2 still fail with the same FLTMGR.sys BSOD immediately after the first reboot. Even non-feature cumulative updates sometimes break Windows Update afterward with “We couldn’t connect to the update service,” requiring me to reset SoftwareDistribution.

At this point, with no third-party FSFilter drivers remaining and system file checks passing, I’m unsure why FLTMGR.sys is still crashing during the upgrade phase. What additional diagnostics or logs can I collect to determine what is causing FLTMGR.sys to fail during the 24H2 installation process, and is there a known issue on certain hardware configurations that could cause this behavior?

The device model is Dell Optiplex 7060. There are devices that have updated to 24H2 and even 25H2 without failure but certain ones install the update and show the aforementioned errors on restart. Any assistance would be appreciated.

Answer 1

Hello Rubal Pradhan,

I can tell you’ve already done a very thorough round of troubleshooting.

Here’s how I’d approach this next:

The most useful diagnostic step is to capture the setup logs that Windows generates during the upgrade. These are stored under C:$WINDOWS.~BT\Sources\Panther and C:\Windows\Panther. The key files are setuperr.log and setupact.log. They record exactly what happens during the transition phase when the system reboots into the upgrade environment. Reviewing those logs often reveals whether the crash is triggered by a driver load, a filter attach, or a storage stack issue.

In addition, since the BSOD references FLTMGR.sys and sometimes NTFS.sys, I’d recommend enabling memory dump collection (set to “Automatic memory dump” or “Kernel memory dump” in System Properties → Startup and Recovery). After the crash, you can analyze the dump with WinDbg or submit it to Microsoft support. The dump will show which driver or component called into FLTMGR at the time of failure.

It’s also worth checking whether these Optiplex 7060 units have subtle differences in storage configuration compared to the ones that upgraded successfully. For example, RAID vs AHCI mode in BIOS, or different NVMe firmware revisions, can cause filter manager crashes during upgrade even when everything looks fine in day‑to‑day use.

As for known issues: there have been reports of upgrade failures on certain Dell models when Dell SupportAssist OS Recovery drivers were previously installed, even if they’ve been removed. Residual registry entries or leftover filter references can still interfere. A clean removal using Dell’s official cleanup utility or a fresh install of Windows 11 23H2 before attempting the upgrade sometimes resolves this.

I hope this helps,

If this guidance proves helpful, please kindly click “Accept Answer” so we know we’re heading in the right direction 😊. And of course, I’m here if you need further clarification or support.

Domic Vo.

Answer 2

To troubleshoot the SYSTEM_THREAD_EXCEPTION_NOT_HANDLED (0x7E) error related to FLTMGR.sys during the upgrade from Windows 11 23H2 to 24H2, consider the following steps:

1. Check for Hardware Compatibility: Ensure that the Dell Optiplex 7060 is fully compatible with Windows 11 24H2. Sometimes specific hardware configurations can lead to issues during upgrades.
2. Review Event Logs: Use the Event Viewer to check for any critical errors or warnings that occurred around the time of the upgrade failure. Look for logs related to FLTMGR or other system components.
3. Memory Dump Analysis: If you have access to a memory dump file from the crash, analyze it using debugging tools to identify the root cause of the failure. This can provide insights into what specifically is causing FLTMGR.sys to fail.
4. Safe Mode: Attempt to boot the system into Safe Mode and then perform the upgrade. This can help isolate the issue by loading only essential drivers and services.
5. Driver Verification: Even though you've removed third-party filesystem filter drivers, verify that all other drivers are up to date, especially those related to storage and chipset. Sometimes, outdated drivers can conflict with system processes during upgrades.
6. BIOS Settings: Check the BIOS settings for any configurations that might affect the upgrade process. Resetting the BIOS to default settings can sometimes resolve compatibility issues.
7. Clean Boot: Perform a clean boot of Windows to eliminate the possibility of startup programs or services interfering with the upgrade process.
8. Contact Dell Support: Since this issue appears to be specific to certain Dell devices, reaching out to Dell support for any known issues or additional troubleshooting steps may be beneficial.

If the problem persists, consider collecting logs from the Windows setup process using the setupact.log and setuperr.log files located in the C:\$WINDOWS.~BT\Sources\Panther directory. These logs can provide detailed information about what occurred during the upgrade attempt.

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References:

• Bug checks (stop code errors)
• Advanced troubleshooting for stop code errors