r/MDT

Last Thursday, after making no changes to our images, cat5 adapters just stopped working on all models, which is less than ideal since half of our devices don't have on board NICs. I redid all the PE drivers, looked up specific drivers for the adapters and added them, and same deal. error 0xc0000001 windows failed to load. The image still works perfectly fine when plugged into an onboard NIC. I've had things like this happen before, but usually redoing the PE drivers fixes it, and im kind of at a loss. Anyone else running into this?

August 2026's patch Tuesday fixes a vulnerability in TFTP server remote code execution, CVE-2026-62893.

• ref: https://www.sentinelone.com/vulnerability-database/cve-2026-62893/

Affected service: WDS

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62893

Post installation of KB5121650 addresses this vulnerability.

If you find yourself able to PXE boot, but get boot up errors, check your MDT server and open up server manager. Go to WDS and under Events, search for 4101 - "the following client failed TFTP download..."

If you that error, open up the WDS application.

• Expand Servers > right click on your mdt fqdn instance > properties > TFTP
• and uncheck "Enable Variable Window Extension"
• Restart your WDS services and try to PXE boot again.