I had created a virtual machine Xubuntu 18.04.1, using Virtual Box 6.0 (on Windows 10 x64), initially with 10 Gb of space.
I needed to resize it to 20 Gb through the Windows command:
.\VBoxManage modifyhd "C:\Users\user\VirtualBox VMs\xubuntu\xubuntu.vdi" --resize 20000
Virtual Box is showing the correct space:
But when using Gparted, it's not recognizing the unallocated space:
What is wrong?