virtualbox.org

I recently bought a new external hard drive to use for VB. I restored the new machine after I transfered the vhd to the external hard drive. Any idea how I can add the snapshots I've made? The restore snapshot option is grey'd out.

It doesn't say anything about snapshots...

It doesn't need to. Snapshots have no bearing on the correct procedure. You need to undo what you have done, then follow the procedure to do the VM move properly. If you are moving individual files from the VM file set then you are not doing it right.