Please note that the installation was carried out without any problems, but from the beginning the disk shown is only 140MB and not 20GB. The first installation menu shows that disk 1 is 20GB and that is the one I selected.
Despite this inconvenience, the system appears fast and stable.
I show some screenshots to illustrate my explanation.
But once the system is installed it indicates that the disk is only 140MB.
EDIT: Later I remembered that on the other machine I upgraded to 1.3 while the installation ISO is 1.2.2 which is the download offered on the official page to install on Virtual Machine. This version difference will be what makes the detected hard drive different in both virtual machines.
The problem was using the VirtIO type virtual disk. I changed it to SATA and it now recognizes much more space but not completely. Of the 64GB Umbrel indicates that 45GB are available.
The problem is not so serious now but I would like to be able to use all the available space. The problem may have to do with the partitions that Umbrel creates during installation. I did a test with a Gparted live ISO but the only thing I achieved when expanding the partition to the entire available disk was to break the system because it locked up root.