From the logs:
Setting up grub-pc (1.99~rc1-13ubuntu3) ...
Installing new version of config file /etc/grub.d/05_debian_theme ...
/usr/sbin/grub-probe: error: file not found.
Auto-detection of a filesystem of /dev/sdb4 failed.
Please report this together with the output of /usr/sbin/grub-probe
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https://bugs.launchpad.net/bugs/769678
Title:
package grub-pc 1.99~rc1-13ubuntu3 failed to install/upgrade:
subprocess installed post-installation script returned error exit
status
