Hi Hmm888:
It might be more accurate to say until such time it no longer cleans Chrome or Firefox (or even Windows) without corrupting something.
At some point in the future changes will be made to way that data is stored by Win 11 and/or your browser of choice that will inevitably be damaged by a CCleaner v6.39 cleanup, and you won’t have any warning until the damage is already done.
Something like this already happened a few years ago. See APMichael’s 27-Jul-2020 post in circcc’s Problem with Firefox 79 about how CCleaner v5.69 wiped out custom settings in many Firefox v79 extensions like uBlock Origin, etc. because Piriform / Avast did not modify CCleaner to take into account that Mozilla had changed the way that browser extension information was saved in Firefox 79’s *.sqlite-shm and *.sqlite-wal files in the user’s Firefox Profile. As a result, users who had CCleaner configured to clean Firefox’s Internet Cache suddenly discovered that all the custom settings, exceptions and/or filters they had created for several of their browser extension were deleted without warning.
This is just one reason why I stopped using CCleaner to clean my default Firefox browser several years ago and configured Tools | Settings | Privacy & Security | Browser Privacy | History | Clear History When Firefox Closes | Settings so my most of my browsing history is automatically purged each time I close my browser.
Dell Inspiron 15 5584 * 64-bit Win 10 Pro v22H2 build 19045.7184 * Firefox v149.0.2 * Microsoft Defender v4.18.26030.3011-1.1.26030.3008 * Malwarebytes Standard v5.5.3.246-153.1.5565 * Macrium Reflect Free v8.0.7783 * CCleaner Free Portable v6.39.11548 * HDCleaner Portable 64-Bit v2.095