Fatal error updating my Arduino UNO Wifi firmware

I was following this guide:

Everything was going well untill I clicked on "Update Firmware". Then at 70% of the progress bar, if froze and, after 20 minutes I noticed it was not responding. Ijust pressed "Esc" and it closed. When I tryed to do it again I just got the pop-up message "Can't communicate with programmer!" after clicking "Test connection".

Does anybody know what I can do?
I would be VERY thankful, because I have no idea and I can't find anything else to solve this.

Try going to the other arduino site for issues with thier software this is DOT CC not DOT ORG.

Okey, I finally could do it.