Just wanted to inform you about weird glitch. My Windows Defender (WD). The process/file name MsMpEng.exe began utilizing constantly about 12% CPU (i7-6700K). Couldn't use LR (6.9) at all. Any operation (e.g. spot removal or even next picture view) would take up to 3 minutes. The weird thing is that WD did not slow down my system (Win 10x64). I hardly recognized that WD is active all the time after thorough investigation. Thought it is just another scan, which however was not the case even after disabling the WD real-time protection.
After researching the possibility for infection and found no infection (kind of have been in AV field for some time so know a few tricks) I checked and found that
Why and how did this happen?
Simply all began after another Win update.
I write this for anyone that might experience the same problem.
Seems odd to need to exclude your WD folder.
You might want to send a note to Microsoft about this.
I have my pictures folder excluded. Not sure if that actually helps anything or not.
If I were you I wouldn't exclude the pics folder, since there are viruses that can and do utilize photo extensions like that one.
As for the WD. Don't know why. However they will ask me to provide full sys info plus dumps, debug logs (AV program debugging is quite extensive and therefore exhausting). Honestly not quite the fan of that. After all it is supposed to be a protected program folder (not that it's perfectly safe) location. ;-)