http://thevlab.net/vmware/tips-and-tricks/extending-a-vsphere-win2k3-os-drive/
Extpart.exe error “Unable to connect to C: or it does not exist”
When you try to expand C: drive using extpart.exe you get the following error:
“Unable to connect to C: or it does not exist”
Here are some workarounds you can try:
1. Close Windows Disk Management console. It’s using Logical Disk Management service which extpart.exe is using.
2. Make sure there are no snapshots
3. Stop some non-essential services i.e:
• Windows Search
• Indexing Service
• File Replication service
• DFS Replication service
Also stop Logical Disk Management service If it shows running status.
