Hi, I've come across a problem: V vocal is accessible on some clips but not on others, even 2 clips in the same track, on one v vocal works and on the other it is greyed out. I've checked the properties of the clips and all seems the same. I'm tearing my hair out. Can anybody help? Asus, corei7, Win 7... bucket loads of processing power...

You may have AudioSnap enabled on some clips. Bounce them and then they should be OK.

Thanks for this - audiosnap is off and I have tried bouncing to clips and bouncing to a new track, to no avail. I'm really puzzled. Any other ideas?

Copy the clip where V-Vocal is greyed out to another track and see if you can use V-Vocal there. 

Hi, yes, I've tried that. I have 2 clips on the same track, one can be opened in v vocal and the other has the menu greyed out. There must be some setting on the clip itself that I cannot find. I sorted all the usual settings, no audiosnap, no effects, no processing at all.

Has clip been changed to a groove clip?
 
Just a thought.

jb101 may have hit the nail on the head. v-vocal will not work on grooveclips

jb101 may have hit the nail on the head. v-vocal will not work on grooveclips

You may also want to check whether any of the locks are on.  I think data would be a key one in this case. 
 

I've no groove clips n this song and no locks on... it's a mystery.