(The original blog on this topic is here)
Recently KB 924148 has been updated with relevant information regarding this problem.
The guidance provided by this KB is current and should address the issues associated with CPU performance consuming the client system during ITMU scans. The new .CAB provided that is already posted has addressed the original issue identified. Further exploration is continuing to ensure that we do not run into this issue again and to optimize performance. Also I’d like to mention that we are working to update the KB to make it more clear. It should be refreshed in a couple of days.
Please note that as per the KB - CPU usage is likely to continue to reach 100%. This is not the source of the problem but is a commonly seen CPU usage associated with scanning. The process is going to use all of the CPU that it can. The change you should see with the latest CAB file is that this CPU usage should no longer lock the client preventing other applications from being responsive.
It is worth noting here that further optimizations (as indicated in the KB) may be possible which are unrelated to the .CAB file itself and if they should be confirmed these will likely be noted in a separate update. The current path of investigation is in the area of how scanning for MSI updates is performed. Should further information be developed I’ll update this blog again at that time.
Please review KB 924148 and confirm that you have the latest .CAB file in use!