problem recalling mix between 2 systems

I carry my main project SSD whilst mixing between 2 systems in different locations. Until now this has not been a problem. Seems since 9.5.10 : some settings are not remembered on some plug ins. Reaktor 6 and SPL drumxchanger do not load correctly as though they cannot see the source library. The Neve 6144 DDMF eq plug in does not remember settings - used extensively on this particular mix. Anyone with similar experience or any suggestions.
With thanks,

Could it be that you have vst2 in the one project but are loading vst3 instead in the other (or vice versa)??

Thanks Grim - I will check that.