I installed Ubuntu 20 in Vmware player. I liked it alot. it was fast and snappy and well featured but one thing bugged the crap out of me. Maybe I’m just not doing it right but when I booted the ISO ubuntu automatically started installing to my virtual hard disc and didn’t ask before formating it. I would install Ubuntu as a native OS but I’m afraid it will format the partitions that I want to keep.
Ubuntu has multiple products, Ubuntu Core 20 is likely closest to Ubuntu 20 (as there is no Ubuntu 20).
I’m not very familiar with Ubuntu Core 20, but on Ubuntu 20.04 LTS for desktop & servers, I’ve never had it launch into the installer, and if it did, I’d assume the ISO was corrupted, or write to your install media was likewise corrupted (you likely weren’t even using media but the ISO itself, given it was a VM). If it’s a desktop or server install, did you verify your ISO?
It’s also possible, given you didn’t use a valid name for a Ubuntu product (there is no Ubuntu 20), you were using a fake, spin, respin or something else completely.
Hmmm. My test environment does not autoinstall as you describe.
Please file a proper bug report detailing, step-by-step, how to reproduce the issue on a stock VMWare Player setup using a current .iso from https://cdimage.ubuntu.com/.
It’s also unclear why you would want to dual-boot within a VM Guest. The whole point of a VM is that you can run each OS independently…