EV addin 10.0.4.1293 not loading with Outlook 2010

Hi

We've just started rolling out EV Outlook add-in 10.0.4.1293 and we're seeing an unexpected issue with Outlook 2010. Multiple users are reporting that the addin fails to load after the upgrade and the workaround seems to re-create the mail profile. One thing we've noticed is that if a PST is attached to Outlook then EV fails to load. Once we remove the PST the add-in loads up again. Any advice?

Previous EV addin version we had installed is 9.0.1.1073

Thanks
Stephan