Pack and Go not moving all assemblies

We are using SolidWorks Office Premium 2010 x64, SP4.0.  We have a large assembly on a network drive and we use pack and go to copy the entire assembly to a local drive.  However, there is one subassembly that does not get copied over.  If we open the assembly from the local drive, it is still referencing the subassembly files from the network drive.  Is there some reason why a subassembly would not copy over and be re-referenced?  Is there any property or setting that would cause this?

We have tried it on a few different machines with always the same results.

Thanks, Tom

SolidworksAssemblies