PXE boot troubleshooting checklist

Symptoms to confirm

• The firmware shows errors such as PXE-E51 (no DHCP offers), PXE-E53 (no boot filename), PXE-E55 or PXE-E78, and nothing appears in SMSPXE.log.
• The device gets an address, then the boot is aborted and it moves on to the next boot device.
• TFTP errors such as PXE-E32 (TFTP open timeout) while downloading boot files.
• WinPE loads, but restarts before the task sequence wizard appears.

Likely causes

A PXE boot is a chain of four stages, and each fails differently:

• SMSPXE.log lives on the PXE-enabled DP, normally in <drive>:\SMS_DP$\sms\logs.

Checklist

1. 1

   Prove the broadcast reaches the DP

   PXE boot the device and search SMSPXE.log for its MAC address. If it never appears, the problem is the network, not Configuration Manager:

   • When the client, DHCP server and DP are on different subnets or VLANs, the router needs IP helpers that forward the client's broadcasts to both the DHCP server and the PXE DP.
   • Open UDP 67 and 68 (DHCP), 69 (TFTP) and 4011 (BINL) between the client, DHCP and the DP.
   • Remove DHCP options 60, 66 and 67 at server and scope level. Microsoft doesn't support controlling PXE with them, and they often push the boot down the wrong path. The only exception is WDS sharing a server with DHCP, which needs option 60 only.
   • Test with the device on the DP's own subnet. If it boots there, fix the routing.
2. 2

   Check the DP's PXE settings

   Open Administration › Distribution Points, select the DP and choose Properties › PXE. Confirm:

   • Enable PXE support for clients and Allow this distribution point to respond to incoming PXE requests are on.
   • Enable unknown computer support is on if you image bare-metal devices.
   • If Network interfaces is limited to specific interfaces, the listed MAC addresses are correct.
   • If several PXE servers share a network, the PXE server response delay decides which one answers first.

   Note: The certificate configured in the DP's properties is handed to PXE clients so they can talk to the management point. If your management points use HTTPS, import a PKI certificate rather than using a self-signed one.

3. 3

   Make sure a PXE-enabled boot image is on the DP

   In Software Library › Operating Systems › Boot Images, open the boot image used by your task sequence and, on the Data Source tab, select Deploy this boot image from the PXE-enabled distribution point. Distribute it to the DP and confirm success under Monitoring › Distribution Status › Content Status.

4. 4

   Read the boot decision in SMSPXE.log

   When the device is found but nothing is deployed to it, the log looks like this:

   MP_LookupDevice succeeded: 16777299 1 16777299 1 0
   00:15:5D:00:19:CA, 32E5B71A-B626-4A4B-902E-7F94AD38B5B3: device is in the database.
   00:15:5D:00:19:CA, 32E5B71A-B626-4A4B-902E-7F94AD38B5B3: no advertisements found
   00:15:5D:00:19:CA, 32E5B71A-B626-4A4B-902E-7F94AD38B5B3: No boot action. Aborted.
   00:15:5D:00:19:CA, 32E5B71A-B626-4A4B-902E-7F94AD38B5B3: Not serviced.

   What you see	Meaning	Fix
   device is in the database, no advertisements found	Known device, but the task sequence is deployed to unknown computers or another collection	Add the device to the target collection, or delete the stale record (search by MAC or SMBIOS GUID)
   Unknown device, no boot action	Nothing deployed to unknown computers	Enable unknown computer support and deploy to All Unknown Computers, made available to media and PXE
   Required deployment ignored on re-image	The device already ran that required PXE deployment	Right-click the device or collection and choose Clear Required PXE Deployments
   No line with the MAC at all	The request never arrived	Back to step 1

5. 5

   WinPE starts but the task sequence doesn't

   Press F8 (command support must be enabled on the boot image) and run ipconfig. Then open X:\Windows\Temp\SMSTSLog\smsts.log and look for Found network adapter with a valid IP address.

6. 6

   Last resort: reinstall PXE

   Clear Enable PXE support for clients, confirm the removal in distmgr.log (DP on the site server) or smsdpprov.log (remote DP), and — if you used WDS — remove WDS, restart and delete the RemoteInstall folder. Re-enable PXE and redistribute the boot images.

Verify

• PXE boot the device. SMSPXE.log shows its MAC address, and the boot action reply now carries your deployment and boot image IDs instead of empty values.
• The device downloads the boot image without TFTP errors and WinPE starts.
• The task sequence wizard (or your required deployment) starts, and smsts.log shows the network adapter with a valid IP address.

Prevent it next time

• Use IP helpers, never DHCP options, for PXE across subnets.
• Prefer the PXE responder on DPs that don't need multicast.
• After a Windows ADK update, refresh boot images and redistribute them before the next imaging day.
• Be careful with required PXE deployments: devices that boot from the network first can start a task sequence without anyone touching them.