How many Partitions are you moving? how big is the C: Partition?
I've run into this (the F: partition was 1.5 TB and I didn't want to redo the entire migration) so I remigrated the C: partition (go to vSphere, browse datastore, and delete out the original main VMDK and VMX files. Run the converter again and migrate JUST the OS partition. Browse the datastore and add all the files to the same datastore folder (generally it will create a new folder with the same servername -1). Once you've placed everything together right-click the .VMX file and add to inventory.
I know it sounds like a lot of work but it only takes a few minutes and its better than re-migrating the whole server.
Hope this helps.