Has anyone else experienced this?
I experience this issue as well.
Based on my observation, it took 2/3 of total CPU resource, while the rest (1/3) taken by Microsoft Security Essential. It seems both are in competition of CPU resource. This sync operation took almost all CPU resources and caused overall Windows experience
to be unresponsive. I still don't understand why a file deletion operation would hog the CPU.
I'm using Windows 7 Ultimate x64 and SyncToy 2.1 x64, and syncing from a notebook harddrive to a USB external harddrive.