Microsoft now detects CCleaner as a Potentially Unwanted Application

"In a new threat entry added today to the Microsoft Security Intelligence site, Microsoft is now classifying CCleaner as a PUA:Win32/CCleaner threat.
... Microsoft has told BleepingComputer that this detection is only targeting the free version as it includes bundled "offers" for other software."

Full text:
https://www.bleepingcomputer.com/news/microsoft/microsoft-now-detects-ccleaner-as-a-potentially-unwanted-application/

Comment:

-Well we have seen concerns about Ccleaner bundling unwanted apps before, especially after Piriform was acquired by Avast. It is why I froze my Ccleaner version on Windows 7 a few years ago. After I upgraded my old Win7 to Win 10, Ccleaner stopped working.

So tonight I downloaded the latest ccestup569.exe and ran it on a test Win10 PC using the "customize" install option. These install options included no default bundled software. It did offer to install a free version of AVG antivirus, which I declined. The install was uneventful. Ccleaner worked well as before, and a quick scan by Windows Defender (now called Microsoft Defender, after the May 2020 upgrade in its ongoing pusuit of obscurity by alias) did not object to Ccleaner.

Bottom line:
- My read is that Ccleaner got caught by Microsft Defender with potentially unwanted bundled software after the May 2020 feature upgrade. I didn't see it because I was still using the older version (Windows Defender) and I had not attempted to obtain the latest Ccleaner for a few years.
- I still find Ccleaner a useful utility for many reasons, but I no longer trust it. Do not allow it to auto-update. If you feel compelled to get the latest version, always choose the custom install method, which allows you to reject optional installed software.