we have started to spread AcyMailing 5.7 yesterday and it appears that Windows Defender identifies the downloadable package as a virus to destroy it.
This is, of course, a FALSE POSITIVE match, there is nothing to fear from this package. We found that any ZIP file with the word "mail" in it is detected as a threat by Windows Defender. So we have changed the name of our package from com_acymailing to com_acym. This way, there's no more troubles with it. We sent an email to Microsoft Services to talk with us about this issue.
YOU ARE TOTALLY SAFE TO DOWNLOAD ACYAMILING 5.7 PACKAGE.
Best regards, Acyba's support team.