Strange Windows 7 Security Monthly Quality Rollup Update failure

Solution 1:

The error code 0x80073aa2 means ERROR_EVT_CONFIGURATION_ERROR. So there is an configuration issue regarding Windows Events.

Looking in your CBS.log shows that the configuration for Microsoft-Windows-RPCSS is damaged:

2017-11-16 10:07:19, Error CSI 00000002 (F) Logged @2017/11/16:18:07:19.635 : [ml:284{142},l:282{141}]"EventAITrace:Provider Microsoft-Windows-RPCSS{{d8975f88-7ddb-4ed0-91bf-3adf48c48e0c}} is missing the channel name for the index key (null).

2017-11-16 10:07:19, Error CSI 00000003 (F) Logged @2017/11/16:18:07:19.698 : [ml:170{85},l:168{84}]"WmiCmiPlugin wevtcfg.cpp(2271): InstrumentationManifestAssert failed. HR=0x80073aa2."

To fix this, run regedit.exe, go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion‌​\WINEVT\Publishers\, press CTRL+F and search for Microsoft-Windows-RPCSS. Now you see the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion‌​\WINEVT\Publishers\{‌​d8975f88-7ddb-4ed0-9‌​1bf-3adf48c48e0c} where the Microsoft-Windows-RPCSS events are stored.

So delete the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion‌​\WINEVT\Publishers\{‌​d8975f88-7ddb-4ed0-9‌​1bf-3adf48c48e0c} and now Windows Update should install fine.