Well, that didn’t last long. I’ve unmarked this topic as Solved after reading donb1’s 15-Nov-2024 CCleaner Portable ccsetup630.zip Quarantined.
I tried downloading a fresh copy of ccsetup630.zip today from https://www.ccleaner.com/ccleaner/builds and the download was once again blocked in my Firefox browser with the same “not commonly downloaded” warning I was seeing with my problematic ccsetup629.zip downloads back in October 2024 (see image <above>).
I chose to ignore the warning and finish the download and a manual Quick Scan of the ccsetup630.zip file with MS Defender virus definition set v1.421.323.0 (rel. 16-Nov-2024) did not trigger a detection, so I’ll monitor for a few more days to see if it’s quarantined by one of my scheduled Quick Scans.
Dell Inspiron 15 5584 * 64-bit Win 10 Pro v22H2 build 19045.5131 * Firefox v132.0.2 * Microsoft Defender v4.18.24090.11-1.1.24090.11 * Malwarebytes Premium v5.2.1.144-1.0.5088 * Macrium Reflect Free v8.0.7783 * CCleaner Free Portable v6.30.11385