Today I realised that I created all of the group Maya work in Maya 2011. This orignally worried me but there is a way to open it. So for those that don't know:
1. Go to 'Open' like you normally would
2. Click on 'Options' and tick 'Ignore Version'
3. Open it as normal
Of course this only applies if your not using 2011 but now there shouldn't be a software block without losing anything (I hope) All the ones I tested opened normally.