WUAHandler.log error OnSearchComplete - Failed to end search job. Error = 0x80240439

Abhijitsworld All error codes indicate communication issues between the Windows Update Agent on the affected systems and the WSUS Server/Software Update Point:

• 0x80240439: WU_E_PT_INVALID_FORMAT - The data received does not meet the data contract expectations.
• 0x80072f78: WININET_E_INVALID_SERVER_RESPONSE - The server returned an invalid or unrecognized response

The PT component reporting the first errors in WindowsUpdate.log is responsible for synchronizing update information from the WSUS Server/SUP to the local datastore, so that may be corrupted. Also check what the difference is between the systems that do scan successfully and the ones that don't: OS version, Windows Update Agent version? Make sure that WSUS/SUP is well maintained. See https://support.microsoft.com/en-us/help/4490644/complete-guide-to-microsoft-wsus-and-configuration-manager-sup-maint for more information on that.