Antivirus is a well known culprit and is almost always a FALSE POSITIVE.
Think about it with logic and you are writing programs !
Most Antivirus works from a well known list and often gets uppity when it comes across somebody writing code it does not understand.
He needs to add exclusions for at least two of these locations depending on how your computer is set up.
C:\Program Files (x86)\Arduino
C:\Users\user\AppData\Local\Arduino15
C:\Users\user\AppData\Roaming\Arduino15