Windows update related error code references

The resources below contain definitions for various error codes that might be seen with Windows Update.

Individual official MS sources

• WUA Success and Error Codes

• WUA Networking Error Codes

• Windows Server Update Services 3.0 SP1 Operations Guide Appendix G: Windows Update Agent Result Codes

• Microsoft Agent Error Codes

• COM Error Codes (Security and Setup)

• Windows Update error code list

• WinINet Error Messages

• WinHTTP Error Messages

• System Error Codes

Merged/compiled list of Windows Update Agent result/return/error codes

• Windows Update Agent - Error Codes