We ran into similar issue. We resolve it by renaming the vmx.lck file then simply added the VM to inventory. Let me give scenario we ran into,
Power outage occurred all hosts and Dell Equalogic SANs attached to 2 UPS's in same rack. UPS 1 failed, 1 SAN went offline and a switch. started shutting down VM's and the other UPS died. Needles to say the VM's were in process of vmotion I think because of one host was also shut down.
Power returned and exchange would not start. VM said orphaned. Removed from inventory and tried to add back in and vmx was greyed out. went to 2nd host and tried, vmx was also greyed out. 3rd host i was able to add to inventory but the VM would never load, imported as orphaned no file name. I removed it from inventory on host #3
Browsed the data store on host #3 where exchange was located and renamed the vmx.lck file and then right click the vmx file and added it back into inventory. The VM appeared in inventory with correct naming convention and powered on in safe mode.A couple reboots later and we were back in business.