I keep getting a message to reinstall parallels tools to correct required kernel modules being missing. I have done this several times and I continue to get the same message. The image quality of Ubuntu continues to look bad.
Same here, standard Ubuntu 17.10 (64) installation (more memory than proposed though) on Parallels 12 and reinstalled PT already a couple of times - to no avail. Regarding the kernel that is. Resolution on my iMac (1920x1080) is fine or can't be made better due to the limited graphics adapter.
Ubuntu 17.10 simply isn't supported yet. This happens with nearly every Ubuntu release. Parallels doesn't seem to even be in a hurry to update their tools to support current Ubuntu releases. http://download.parallels.com/desktop/v13/docs/en_US/Parallels Desktop User's Guide/
"...doesn't seem to even be in a hurry" is a nice way to put it . April and Ubuntu 18.04 (almost) here and still the same problem with Parallel Tools, i.e. get the error message with every boot. According to https://forum.parallels.com/threads...linux-support-ubuntu-17-x.341886/#post-827583 Desktop 13 should support current version s of Ubuntu. But after following the forum here every now and then (and based on my experience with the support in past releases) an upgrade to Desktop 13 wouldn't help either. It just the way it is.