Error trying to install adafruit SAMD

I'm trying to install the Adafruit SAMD Boards package for my Adafruit QTPY microcontroller. Sadly it won't download.

I have no idea what causes it.
What I tried to fix it

  • Dissable anti-virus
    *Start Arduino IDE as a developer (windows)
    *Restart my computer a few times.
    *Other versions of the package

Try installing the cores manually following this article: How to install and use a custom core version in the IDE – Arduino Help Center

I can't believe it... I fixed it by dissabling my whole antivirus. I had to dissable the documents map in AVG FREE... Now it did install. the topic can be closed.