Many Windows Updates require you to restart the system once the update has installed. Usually, you could wait to complete their work and restart the system as per your convenience, but at times, you might get the error:

Windows Update Error 0x80242014

The official description for the error is "WU_E_UH_POSTREBOOTSTILLPENDING: The post-reboot operation for the update is still in progress."

Rebooting the system becomes necessary in this situation, and in most cases, it would resolve the problem.

In case the issue persists, you might consider running the Windows Update troubleshooter.