If an EA was compiled on a Windows System, can it be used without modification on a Mac?

 

Bear in mind, please, that the meta trader 4 platform has a different versions for Windows and for Mac operating systems.

Input will be appreciated.

Thanks!  :) 

 
AFAIK, MT on MAC is just a bundle containing Wine and MT virtual image for it. The MT is a standard Windows terminal, so you can use all EAs, indicators and scripts "as is". MetaTrader is a platform itself in the sense of providing execution environment for its scripts, and this "internal" environment is OS-independent.
 

Thanks