I have the feeling there where some packages (kernel headers and extra's) missing from the first upgrade. Maybe it was just too soon that I executed the upgrade while these missing packages where not released yet? In any case, gonna answer my own question here to share the steps it took to resolve this:
- reboot and select the advanced boot options at the Grub boot prompt, then choose the previous 16 kernel and boot with that.
- log in and open Software Center, search for "kernel 17" (without the quotes)
Now check if "linux-headers-4.2.0-17" and "linux-image-extras-4.2.0-17" are not installed. If they are in the list but not installed, you may try to install them direcctly (don't know if that will fix it) but because I was not sure I proceeded with removing the 17 kernel first:
- select "linux-image-4.2.0-17-generic" in the short list (you may need to click the "Show technical items" link at the bottom) and hit the Remove button
- confirm the question to remove "linux-signed-image-4.2.0-17-generic" and "linux-image-generic" too
- open the Update Manager and let it run.
Update Manager should tell you there are new kernel upgrades. If it doesn't, then go back to the Software Center and search for "linux-image-generic" and install that.
Let it upgrade/install all packages (more than the first time!) and reboot.