System Thread Exception Not Handled

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SYSTEM_THREAD_EXCEPTION_NOT_HANDLED on startup

Use this page when the stop code hits during boot or right after sign-in, but you are not stuck in a continuous reboot loop. Order: identify module → Safe Mode → driver/startup cleanup.

First cut Continuous BSOD-reboot with no usable desktop time → boot loop. Crash only after gaming/load with nvlddmkm → nvlddmkm. Crash only after yesterday’s patches → after update.

Step 1 — Capture stop code and module at boot

Disable automatic restart if needed, photograph the BSOD, or pull the newest dump via minidump. Write down any .sys name.

PC monitor showing a blue screen during Windows startup with the stop code circled
Startup crashes still expose the same 0x7E stop code and optional module name.

Step 2 — Boot Safe Mode

Follow Safe Mode. If Safe Mode also fails immediately, escalate to boot loop WinRE repairs.

Step 3 — Driver and startup cleanup

  1. Device Manager: roll back display, storage, network, and HID/touchpad drivers changed recently.
  2. Task Manager → Startup apps: disable non-Microsoft entries that load at logon, then retest a normal boot.
  3. msconfig → Services → hide Microsoft services → disable third-party services temporarily for a clean boot test.
msconfig Services tab with Hide all Microsoft services checked and Disable all highlighted
Clean-boot test: hide Microsoft services, disable third-party services, then re-enable in batches.

Re-enable services in small batches so you can see which one returns 0x7E.

Step 4 — Startup Repair

If drivers look clean but boot still throws 0x7E before the shell, run WinRE Startup Repair, then reconsider storage drivers and ntoskrnl / memory checks.

Branches

Module named nvlddmkm · etd.sys · ntoskrnl
After Update after update
Became a full loop boot loop
Need dump minidump

FAQ

Why only on startup?

A driver or service that loads at boot can throw before you open any app. Safe Mode skips many of those start drivers so you can remove them.

Safe Mode works but normal boot fails

That pattern almost always means a third-party boot-start driver or service — stay on this page’s cleanup steps, then the module branch named by the dump.

Official and primary sources

  1. Microsoft Learn — Bug Check 0x7E SYSTEM_THREAD_EXCEPTION_NOT_HANDLED
  2. Microsoft Support — Start in Safe Mode / Startup settings
  3. Microsoft Support — Unexpected restarts and stop code errors
  4. Microsoft Answers — Stop code on startup / after changes
  5. LazyAdmin — System Thread Exception not Handled fix steps

Symptom map