Cannot compress disk space

Symptoms

I cannot compress the virtual Hard Disk of my Virtual Machine.

After I click on "compress" nothing happens, the size of the Virtual Hard Disk remains the same.

Resolution

1. Make sure your Virtual machine is shut down
2. Go to your Virtual machine Configuration
3. Switch to Hardware tab > Hard Disk 1
4. Click Edit

5. Uncheck the "Split the disk image into 2 GB files"

   

Cause

Virtual Machine misconfiguration.