Were you on a Gridcoin fork ? So, have you tried repairwallet yet ?

"After a few reports of peoples coins going missing or stolen due to a fork..." (see here)

So, go ahead and type in your Gridcoin wallet's !debug console: 

• repairwallet 

You might see e.g. fields 

• 'mismatched spent coins' or 'amount affected by repair'

then restart your wallet afterwards, and you should see your missing coins now.

If you just see: 

• "wallet check passed": true

then all seems fine...

Erkan (find me on IRC and twitter)