CCleaner, a popular PC optimization application, is being flagged as ‘Potentially Unwanted Software’ by Microsoft Defender (formerly Windows Defender, but renamed with the May 2020 update), which is Microsoft’s built-in antivirus for Windows 10.
Potentially unwanted software, more commonly known as Potentially Unwanted Applications (or PUAs), refers to applications with which an antivirus does not find anything malicious, but which may exhibit unwanted behavior of one kind or another.
Usually that means bundling extra parts and pieces, or stealthily installing extras like a browser plugin, which may not harm your PC, but could be a hassle.
As Bleeping Computer discovered, Defender now detects CCleaner as a PUA, and the software giant claims that: “Certain installers for the free and 14-day trial versions of CCleaner come with bundled applications, which are not required by CCleaner or produced by Piriform publisher himself.
“While the bundled applications themselves are legitimate, the combination of software, especially third-party products, can lead to unexpected software activity that can negatively impact user experiences.”
Those included apps include the Google Chrome browser, Google Toolbar, and Avast Free Antivirus plus AVG Antivirus Free (note that Piriform is now owned by Avast, which also owns AVG).
Microsoft further emphasizes that those bundled apps are perfectly fine and not malicious in any way, of course, but it’s the way they are offered for installation that is problematic.
The company notes that while the CCleaner installation process does provide a way to opt out of including these extras on your PC, unsurprisingly, the judgment is that “some users can easily install these bundled applications without realizing it.”
Often these issues are due to the way exclusion options are presented.
In any case, according to a statement just released by CCleaner, the company believes the problem has been resolved.
A CCleaner spokesperson told us: “We are in the process of engaging with Microsoft to understand why CCleaner was recently detected as PUA. We assume that the problem appears to be related to bundling, and we believe we have addressed this so that our product is no longer flagged. “
So it may now be the case that if you are going to install CCleaner while running Microsoft Defender, you are no longer warned to continue, assuming the security app actually updates as CCleaner claims.
