So all the security issues with CCleaner over the years
CCleaner is safe to use and will not infect your machine, most people who still spout this don't know what they are on about.
^^^THIS^^^
First and foremost, the few issues were minor, actually affected only a tiny number of the 10s of millions of users. And the problems were quickly addressed long ago. And it should be pointed out the issue that caused the most attention wasn't even caused by the developers of CCleaner (Piriform). Rather, it was caused by the new owners of Piriform (Avast) sticking their noses in the mix without doing their homework first.
If you believe CCleaner is unsafe, then you should use no 3rd party cleaning tool and just stick with Windows own Disk Cleanup.
Me? I'll stick with CCleaner. Having the ability to keep specific cookies during cleanup is invaluable to me.
And for the record, the claim that CCleaner's Registry cleaner can be harmful is misleading and totally exaggerated too. CCleaner has been around for close to 20 years. It is unreasonable to assume such a popular and useful tool that's been around that long would still be on the market (or, as an included feature) if that harmful as some suggest.
Yes, decades ago, some registry cleaner were reckless and way too aggressive. CCleaner's never was. In fact, if anything, some would suggest it is not aggressive enough. I contend that is what makes it safe. But still, many simply lump all Registry cleaners in one evil heap and that does CCleaners an injustice.
While anecdotal, I personally have used CCleaner's Registry cleaner on 100s of different computers, likely more than a 1000s times. And I never, not once had it brick a computer. Worst case required a simple reboot.
One caveat/qualification - I never use the registry cleaner to "fix" a broken computer - only to maintain it. So, for example, if I replace a NVIDIA graphics card with an AMD (or the other way around), I will run the cleaner after the installation to clean out all the crud left behind by the removed card. After upgrading from W7 to W10, or W10 to W11, once sure everything works, I will run the cleaner.
And for the record, Piriform also has a history of removing features that don't work correctly. For example, Speccy, their HW information applet, used to report PSU voltages as found on the motherboard. But with many motherboards, the reported values were way off, reporting 6.2V for the 12V value as an illustrating example. So Speccy removed that function and no longer reports that. There is no reason to believe they wouldn't remove the Registry cleaner too if it caused problems.
Regardless, whenever messing with the Registry, either by a 3rd party utility, or via Registry Editor, one should always run a backup first.
Oh, and for sure, considering the fact Windows own Registry Editor (regedit) makes changes in real-time, and doesn't even have a backup feature, or offer to backup (or export) BEFORE making changes, I would much rather users use CCleaner, which does offer to backup the registry before making changes. And BTW, the restore feature works - I tested it.