Plugins Reset From Mac -> PC

I use Cubase 7.5 both in the studio and at home. The studio runs a Mac and at home I run a PC. However, when I open a Mac project on PC I find that all my third party plugins (Waves, Native Instruments) have reset. All the settings have disappeared.

Any ideas why this might be? The same is not true the other way round. Opening a PC project on a Mac renders the plugin settings all intact. The problem is bizarre and extremely annoying. I can’t find a solution for it. I can’t even save presets because the PC system doesn’t seem to recognise presets created on a Mac.

Any thoughts would be fantastic.

Happens to me also… Mostly on Lexicon LXP - The reverb settings reset.