I'm using CCleaner professional v5.56.7144 (64-bit) on Win7 SP1 (patched fully)
I've had CCleaner close while doing registry scan for issues, cleaner mid cleaning, and while it was monitoring (minimized to taskbar). I cannot keep it open longer than about 5 minutes or so in /MONITOR, and I cannot find a cause (no malware, checked that from multiple tools, including checking for rootkits).
It just closes, but I'm not able to identify a cause. There is no scheduled task to cause issue, it is not conflicting with any other active task (at least previous versions of CCleaner did not have