As pointed out in numerous recent topics, such as this one, it's almost always from an overzealous antivirus. Try disabling yours for the moment.
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We have a lot of experience with troublehsooting this error for people, although it could technically be caused by any kind of software on the computer, it has always been the user’s virus/security software in every instance we’ve helped with. It’s a common strategy with security software to automatically deleted unknown executables that came from the internet.