System Thread Exception Not Handled

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SYSTEM_THREAD_EXCEPTION_NOT_HANDLED boot loop

A boot loop is 0x7E → automatic restart → 0x7E again before you can use the desktop. Interrupt the cycle with WinRE, then repair drivers or updates from Safe Mode.

First cut Can reach desktop for minutes between crashes? That is not a hard boot loop — use home, on startup, or the module page instead. During Windows setup crashes → during install.

Step 1 — Open Windows RE

Power off during early boot twice to trigger Automatic Repair, then Advanced options. Full Safe Mode path: Safe Mode.

Step 2 — Stop automatic restart on failure

From WinRE Startup Settings choose Disable automatic restart on system failure so the stop code stays readable. Note any faulting file for later module pages.

Startup Settings list with Disable automatic restart on system failure highlighted by a red arrow
Freeze the BSOD on screen long enough to read the module name.

Step 3 — Safe Mode repairs that break most loops

  1. Roll back or uninstall the driver named on the BSOD / dump.
  2. Uninstall the latest Windows update if the loop began after patch Tuesday.
  3. Disable recently installed antivirus or virtualization filter drivers temporarily from Safe Mode.
nvlddmkm.sys on screen NVIDIA branch
etd.sys on screen touchpad branch

Step 4 — Startup Repair and System Restore

WinRE → Startup Repair for corrupted boot files after repeated crashes. If that fails, System Restore to a pre-loop point. Microsoft documents both under Windows RE tools.

Step 5 — When you need install media

If local WinRE is missing, boot official Windows install media → Repair your computer. Avoid random “boot repair” ISOs. Still no progress → copy minidumps off the disk before reset.

Branches

Loop started after Update after update
Fails once at login then OK on startup
Have dumps minidump
Fresh install also loops during install (hardware path)

FAQ

How do I fix a SYSTEM_THREAD_EXCEPTION_NOT_HANDLED boot loop?

Enter WinRE, disable auto-restart, boot Safe Mode, remove the bad driver or update, then test a normal boot. Forum SERPs for this query are almost all “stuck in loop” stories that resolve that way.

Is Automatic Repair itself stuck?

Skip to Advanced options rather than waiting on repeated repair attempts. Use install media if the recovery partition is damaged.

Official and primary sources

  1. Microsoft Support — Startup settings
  2. Microsoft Support — Windows RE
  3. Microsoft Learn — Bug Check 0x7E

Symptom map