What is %LOCAL APPDATA%\CEF?
Some people found %LOCAL APPDATA%\CEF on their PCs. AdwCleaner detects this folder as malicious.
But usually %LOCAL APPDATA%\CEF is a folder for storing data created by applications using CEF.
The Chromium Embedded Framework (CEF) is a simple framework for embedding Chromium-based browsers in other applications:
https://bitbucket.org/chromiumembedded/cef
How dangerous is CEF?
Usually CEF folder contains USER DATA subfolder. It also contains subfolder related to the CEF applications.
My verdict: %LOCAL APPDATA%\CEF cannot be marked as malicious, because it is only a container for sub-folders. You do not delete Program Files if one sub-folder is bad.
How to remove CEF malware?
Some CEF applications may contain adware/spyware etc. In this case I suggest you to delete a subfolder related to the malicious application.
Some legitimate application like Steam, Google Widevine use CEF.
Be careful to avoid damage your PC!
You can always check your PC for adware/malware/TRojans/spyware using UnHackMe.
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