Originally Posted by JimmXinu
Kovid said: Almost certainly an antivrius. Antivirus makers appear to believe that launching processes that communicate with the internet is "suspicious activity".
Ah yes. I actually ditched AVG because every time I updated Calibre to a new version it would identify calibre-parallel.exe as a virus and remove it from my system, requiring me to add a new exception. Super annoying. But if AVG was going to insist "there's only room on this computer for Calibre or me!" the decision was easy enough.