Hi noticed this but never really paid attention to this:

Recently someone from work asked me, that she's got a file on Mac and zipped, sent to a windows user, they can't open it, then I asked her to send it to me, the reason, the other user can't open it, it's the files that embedded into the zip file e.g. _Mac folder and files, is there a way not to include them when zip a file on Mac?

Thanks.

Just tested it mate, worked fine on two Macs and three Windows PCs. All Macs were OS X Leopard and all PCs were Windows XP Pro, worked in both WinRAR and the XP Built-in system

What program did she zip it with? Which OS?

Zipping is cross platform here as well.

_MACOSX folders are seen when opened on Windows machines, but they shouldn't affect anything. The other files should be perfectly intact.

Yeah Zipping is cross platform.

The file may be corrupt.

zip is a file type that should be the same cross platform

You would see the Mac files, but they would be there in addition to whatever you zipped. If you can't open whatever that is, there's something else going on - the Mac files won't do anything on Windows, they're just there.