I have never had a single issue using the registry cleaner part of CCleaner. Been using it for years, including on Windows 10 now.
I use CCleaner and got the pro version have used it on all my computers and laptops even installed it on friends of mine.
Any trouble big Answer is NO
My friends computer was lagging and shutting down run CCleaner and Disk Defragger and it went from being nearly thrown through the window by him to now very fast.
Only 2 company I trust to install any software from is primaform makers of CCleaner and Auslogics makers of Disk Defraggler and never had any trouble at all.
I have CCleaner Monitoring running in the background and when I shut edge or any forum or page CCleaner cleans the disc and gives me the space back
It is how you use it and don't tick any boxes you are not sure off
When I analyze my disk with Puran Defrag and it shows that the registry, page file, or master boot record is fragmented, I run a boot time scan and it fixes all of those. It's optimization option is also excellent. I run all of these things on all the computers in this house (4 of them with 4 different flavors of Windows) and never have a problem with any.
I regularly used CCleaner and Ghostbuster with Windows 7, just started again with 10. Really useful after removing software and hardware respectively.
I use CCleaner Free & Glary Utilities Free since XP to Win10 so far so good
My experience has been just the reverse of some of the respondents here. I've used CCleaner for years, and never had a problem until I updated to Windows 10. And it wasn't the registry cleaner of CCleaner that gave me problems--it was some files it deleted that made my Start button stop working completely. I've searched around and seen that others have had the same exact issue.
I'm still not sure which files got deleted to cause the problem. But I use CCEnhancer, so it probably was not the built-in CCleaner items that caused the heartache.
I do use CCleaner for registry cleaning. I know it does not make a performance difference, but it pleases me in a neurotic sense. I also know enough about the registry that I'm pretty good at knowing ahead of time what could cause problems. I also backup my registry.
Unlike some junky registry cleaners, CCleaner is pretty conservative about what it deletes. Pretty much everything it offers to delete is due to missing files.
The Registry loads on boot up/the bigger it gets, the more memory it uses/the more memory used, technically the slower the system. The Registry is read with each boot up. You have a registry with 1,800 errors (not an exceptionally large amount). Each error is read and found to be an error and then to the next line in the Registry, and so forth and so on until the Registry is read. [I am just picking number here!] - your registry is 25MB and full of old errors, mine is 10MB with maybe 10 errors - and there is absolutely no difference in performance???
I use Ccleaner to clean the Registry and have for years. Never had a problem and over the years with new O/S's, programs, updates, uninstalls, etc. have removed literally thousands of Registry errors. And all of this has been for naught? Well, I must say, you could have fooled me!
All I can say to edpring is ..... Well said sir, been doing same thing for years, and I mean years!!!! your 100% correct.