I don't really want to buy a virusscanner for mac... I would prefer to use a service to scan the file for me... or use a portable application to scan it (clamav maybe...)
Is there a service out there scanning for bitcoin? Or a way to get past that 128mb limit?
As part of casual help unlike scammers who have messaged you to provide the same for bitcoins (pathetic)
-Is the downloaded file from trusted resources ?
-Avast provides a free version too !
https://www.avast.com/free-mac-security-Avg also has a free version
http://www.avg.com/en-ww/avg-antivirus-for-mac-Use them to scan the file.Again,they're not the best out there but since you don't want to go for a paid version.
-If you are open to,you can buy a VPS and check if the file has a malware remotely.