I've got the same problem, and it will even stop working.
Thus, I have to use the Task Manager to close it.
I noticed that it is working on the Windows Explorer TMP, History, and Cookies when this happens.
OS : Win 7-64bit
Motherboard: MSI: K9N2GM
CPU: AMD Athlon 64x2 Duel Core 5600+
Memory: 8 Gigabyte
Video: NVIDIA GeForce GT 630 {2Gb Memory}
Edit:
I'm including the Debug Log.
CCleaner64_v5.41.6446_2018-03-14_14-11-00.log