What does HRESULT 0x8024201B (WU_E_UH_INVALID_TARGETSESSION) mean?

WU_E_UH_INVALID_TARGETSESSION

The update handler received an invalid target session

WU_E_UH_INVALID_TARGETSESSION means the Windows Update handler expected to install against a particular user or system session, but that target-session context was not valid when the operation ran. This is a session-association problem, not a generic network transport failure.

What to check

• Record whether the update is per-user or machine-wide, the target user/session identity, and the handler operation that produced the HRESULT.
• Correlate the failure with logon, logoff, reboot, service restart, Fast User Switching, or AppX deployment events that could invalidate a previously selected session.
• Use Windows Update and deployment logs to identify the session originally selected and whether the update should instead run in system context.

Recovery

Recreate the update/install operation with a currently valid target session or the correct machine-wide context. Do not troubleshoot DNS, proxy, or endpoint connectivity unless a separate result identifies a transport problem.

Verification should repeat the same update content while changing only the invalid session association. If the handler then returns another HRESULT, keep that next failure separate.

References

• Microsoft: Windows Update error reference
• Microsoft: Windows Update log files