Pour Info... j'ai trouvé...

Le format d'application Max standalone est "cross plattform" si on joint les "externals" particuliers  équivalent à chaque platteforme...

The “new” Max collective format is cross-platform; however, included external objects are not cross-platform, so if your collective uses any non-standard external you will have to supply these as separate files for each platform. If you are going be giving Macintosh- created collectives to Windows XP users, you are strongly encouraged to use the .mxf file
extension. Otherwise, it won’t be possible for Windows XP users to open the files.
(cf:Max45 Tutorials&Topics)

Des infos sur le format .mxf?

Au sujet de pluggo,

Pluggo was first ported to Windows XP at Pluggo version 3.5. Since Max/MSP patches are cross-platform compatible between OS X and Windows XP you can copy your prior Mac pluggo patches to a Windows machine and use the plug-building capabilities in Max/MSP 4.5.3
or later to create Windows VST or RTAS plug-ins. Note that for all externals in your patch Windows XP versions will be required. 

(cf:Pluggo DevGuide35)

Mais:
You create Pluggo plug-ins from MaxMSP patches, so you can make a plug-in by creating it on a Macintosh or Windows machine, and then saving your patch as a plug-in. If you save the patch as a plug-in on a Windows system, you'll get a plug-in that runs on either VST or RTAS host applications on a Windows machine. If you save the patch as a plug-in on a Macintosh, you'll get a plug-in that runs on VST, RTAS or Audio Units host applications (Please note that you can't take a plug-in created on one operating system and run it on the other).

Donc il faut compiler son patch avec  la version MaxMsp de l'OS pour lequel on voudrait créer le pluggin... :cry: