How safe is it to scan for all issues and fix all?

[Demono]

I just downloaded the newest version of CCleaner as of this writing (1.20.118) and I am not sure if the issues scanning was there before or not, but its new to me. Anyway, I scanned for all issues but I am hesitant to clean the results, mainly the ones dealing with unused file extensions. What exactly does it do to "fix" those particular issues? Does it just the reference to the extension in the registry? Does it add a reference to it? Does it delete the files with those extensions? Just want to make sure what I'm doing before I do it Thanks in advance for any info.

[TwistedMetal]

Usually if you uninstall programs it leaves registry settings referring to the file extension. All CCleaner does is removes the invaild extension registry key. I run Issues without backing them up (I trust CCleaner that much). "If" something does go wrong for whatever reason, just back it up. But, I have never had any problems. It has removed 119 invaild entries on my Windows ME computer and it hasn't had one problem.

[englishmen]

Not quite sure but I believe CCleaner has been developed so what it cleans is safe to remove so I would just clean them. CCleaner regulars finds those useless file extensions on my pc and I just remove with no problems. If you are hesitant in removing them just click "Yes" when Cclaner asks if you you wish to create a backup, if any problems arise tho I don't think there will be then just restore the registry files it removed by double clicking the backup file.

[Demono]

Okay, thansk for the info. I didn't realize CCleaner also popped up a confirmation for each issue and explained what the solution was since I was hesitant to fix them in the first place, but now its done and no problems so far