So today I had to extend a system partion on a old windows server 2003. Normally I would use a helper windows 2003 VM to extend the partition but when I tried this I got the same message error “Selected Volume cannot be Extended”. So I had a look on google and found a tool call extpart by Dell. This tool did not work the first time I used it, here I got the error : “Unable to connect to c: or it does not exist”. I then tryed restarting the VM in safe mode to see if the tool will work here  and it worked! So from now on I think I will use extpart instead of the old way of extending a VM piggybacking on a helper. To use extpart download and extract the file on the VM you want to extend the partition. You can download here in case Dell desists to move it from Dell’s FTP site. Run extpart.exe specify the drive you want to extend eg. C: next, in MB, how much you want to extend the drive with and you done!