pyinstaller virus

Hay , Im new in python and try to do a simple Gui and Export it to an .exe file. So i load pyinstaller and make a Exe file with "pyinstaller --onefile file.py". It works perfectly, the only Problem is the terminal open too. So i Google and find out i need to change the .py to .pyw . Now i cant convert it to a .exe because Windows says its a Virus. Its the simples Programm of the World. Can anyone Tell whats the Problem?