Piriform has programmed CCleaner to remove part of the MSE History files and it's deleting the files MSE checks to determine the last time a scan was conducted. When these files are deleted MSE informs you that a scan is needed evey time you reboot. This file removal has no effect on the antimalware protection provided by MSE.
I got the following info from the answers.microsoft blog:
Please see the following compliments of Le Boule:
Are you using CCleaner? Piriform has programmed it for some reason to remove part of the MSE History files and it's deleting the files MSE checks to determine the last time a scan was conducted. This file removal has no effect on the antimalware protection provided by MSE.
Open CCleaner Applications Tab, then Under Windows uncheck MS Antimalware...that should prevent CCleaner from deleting the MS Antimalware scanning history files.
Per suggestion of MartinHampton you may also need to uncheck MS Management Console.
You may need to run another quick scan and reboot the computer.
This process worked for me to fix the problem but I wonder if there is a better way. I did not have this issue with prior versions of CCleaner.
