Neil
 

It depends.
Which plug-ins are missing?
Which version of SONAR?
32 or 64bit?
 
The more information provided the better the answer will be.

Platinum. All updates received. Linear Phase 64 multi  band. LP 64 EQ=Missing. HP ENVY. 12 gigs of ram. Both plugins worked fine until this evening. 

lp 64 multi and lp 64 eq have been updated to vst3. look for the new ones in the vst3 folder. the older ones should be in the vst2 folder. don't know about the hp.

Thanks. Recovered them. I just had to delete the missing vst from the track and drag in the same from the browser. There have been a few others. Don't know why it is happening but when I reach a certain point in this project I am going to wipe and reinstall this machine. Thanks guys.