There doesn't appear to be a "Shake' FX in the native Vegas FX so you probably had it as part of Third Party (such as New Blue) FX package. Do you still have MS14 installed so you can check to see where it came from?
Not all TP FX packages will work with newer versions of VMS.
Thanks for the reply, I see that it is nested under the "third party" column in effects under the "Transitions" banner... I do remember adding a package years ago too interestingly.
So my new question - Is there a way to import the effect from the original download or find a version that is compatible?