for the love of new features, from my point of view having this option ON as DEFAULT is a bug - [discussed below]
I consider ccleaner an amazingly dumb-proof one-click tool for removing garbage from a computer.
For me the genius of CCleaner is that it NEVER deletes anything CRITICAL (unless told to, anyway)
When it deletes OLD (backed up) browser sessions - that's OK, that counts as privacy measure (most people will struggle to even find the files)
But when it deletes my WORKING DOCUMETS [ie web pages] just because i am not looking at them right now, that just feels wrong.
Or maybe I AM werid - because after I close a browser with 15 tabs open, I do expect them to BE there next time i lanuch the browser. Maybe it's because I've been using 'tabs' for ten years?
Of course, it is a workflow preference. Someone else may prefer all open tabs to disappear automatically when they close a browser. Fine - but surely it's kind of weird do it with 3rd-party app, when you can easily[three clicks?] set it in most browsers? [some even ASK you about it!]
As of now it appears that CCleaner "by default" assumes we, users, are too lazy (forgetful, busy, etc...) to close/organize our own browsing session.
Seriously, if I found my girlfriend had cleared&binned my desk in the name of "cleanlines" & "privacy", it wouldn't make me happy, would it?
A compromise maybe, like CCleaner with optional, separate CLEARING & NET-PRIVACY pre-settings? Just an idea...
I can see the real-life practicality of the default setting - but I can also hear couple of hundreds of people scream in disbelief after their sessions disappeared... by the way, do YOU use sessions?
All in all, it's the eternal developer<->user communication loop :-) never perfect...
I recommend CCleaner every week, especially to not-so-geeky-people. Now I will be adding a little warning...
PS> of course... always remember: backup backup backup anyway ;-)