I am using 18.06.1 (on a ESXi virtual machine) and I would like to sysupgrade 18.06.2: I read from docs and threads about sysupgrade but I am not sure about correct procedure.
The VM was originally CC 15.05. When the VM reboots after the upgrade it just enters a reboot loop. Am I doing something wrong? It says there is 35MBs free before I upgrade so I dont think the error is right.
You're trying to upgrade a four-year-old image. Expect problems, especially if you save settings. I can't read your images, so if there are meaningful messages there, posting with the preformatted-text button </> is preferred.
Copy your settings (they're text files), backup any data files you need and install from scratch. Then edit the new config (it has changed significantly from Chaos Calmer) to your liking.
It was two screenshots of a console window, no copy paste ability unfortunately. They show that an error occurs during sysupgrade when mounting /dev/sda and unmounting /mnt both saying invalid argument.