1. Delete all snapshots. (Make sure you have backups)
2. Shutdown the Virtual Machine and use VMWware-vdiskmanager utiltiy (comes with VMWare Workstation) to extend partition.
Example: if you want to increase OS drive of your Windows 8.0 virtual machine (located at "D:\My Vurtual Machines\windows 8\Windows 8.vmdk" ) by 15GB then use following commmand:
C:\Program Files (x86)\VMware\VMware Workstation>vmware-vdiskmanager.exe -x 45Gb "C:\My Vurtual Machines\windows 8\Windows 8.vmdk"
3. If you are attempting to extend the OS drive, you can use some 3rd party partitioning software (such as Partition Magic or Paragon Partition Manager). If you are increasing the size of a data-drive/partition, you can use DISKPART commands in your Virtual Machine.
Example: for extending OS drive, use the 3rd party partitioning software, and allocate the unallocated space as “primary”: then merge it with ‘basic’ C-drive.
If you get error:
Failed to expand the disk "C:\My Vurtual Machines\windows 8\Windows 8.vmdk": One of the parameters supplied is invalid (0x100003e80).
Possibly, you have not created the vmdk file as of fixed size, instead selected option that would let the hard disk volume grow when become larger. So, there might be multiple .vmdk files, and therefore the vmware-vdiskmanager causes the above error.
For this type of vmdk,
Select "Edit virtual machine settings" from VMWare Workstation. then, Hard disk > Utilities > Expand : now expand the hard disk to 45GB
After this, run the virtual machine. Right click the Computer or My Computer: Select "Manage"
In "Computer Management": select "Disk Management": It will show 45GB as unallocatted volume.
Right click your OS-drive (C Drive) and select "Extend volume" and extend it ti complete 45GB.