CCleaner is considered a generally safe cleaner. Thus, all Advanced selections under the Windows tab are unticked by default, presumably for a reason, which may have to do with system stability.

However, in its 8-step Malware Removal Instructions http://www.techspot.com/vb/topic58138.html, TechSpot advises:
My fist question is: What does one gain by including these Advanced selections apart from a little extra space, and even that until it is soon filled up again?

But my main question is: Why does CCleaner leave out these Advanced selections by default? More specifically, what could be the adverse consequences of ticking (selecting) them?

A full item-by-item reply would be most helpful for dispersing (or justifying) fear of selecting them. The tool itself does give some info on each, but this is not always clear. E.g. for Tray Notifications Cache it says “You need to restart the explorer.exe process.” So, how does one restart the explorer.exe process? Don’t we start it anyway every time we click on its icon?

CCleaner (Last updated on 27th January 2009)

The Advanced settings are basically defined on this page: CCleaner Beginner's Guide

Restarting Explorer.exe, is basically done by restarting your computer


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Thanks for the links, it's a lot clearer now.

Reminds me of, "When all else fails, read the instructions".

The only problem is finding what you want in the instructons and of course understanding it. TechSpot can come in useful here.