Seeing this problem as well with the latest LVM package update on unstable.
Setting up dmeventd (2:1.02.171-2) ... dm-event.service is a disabled or a static unit not running, not starting it. Setting up systemd-sysv (246-2) ... Setting up grub2-common (2.04-9) ... Setting up libnss-systemd:amd64 (246-2) ... Setting up grub-pc-bin (2.04-9) ... Setting up lvm2 (2.03.09-2) ... update-initramfs: deferring update (trigger activated) Failed to start blk-availability.service: Unit blk-availability.service has a bad unit file setting. See system logs and 'systemctl status blk-availability.service' for details. Setting up grub-pc (2.04-9) ... Installing for i386-pc platform. Installation finished. No error reported. Generating grub configuration file ... Found linux image: /boot/vmlinuz-5.7.0-2-amd64 Found initrd image: /boot/initrd.img-5.7.0-2-amd64 done Setting up libpam-systemd:amd64 (246-2) ... # systemctl status blk-availability.service ● blk-availability.service - Availability of block devices Loaded: bad-setting (Reason: Unit blk-availability.service has a bad unit file setting.) Active: active (exited) since Fri 2020-06-26 18:15:45 EDT; 1 months 9 days ago Main PID: 227 (code=exited, status=0/SUCCESS) CGroup: /system.slice/blk-availability.service Aug 05 16:59:36 testlaptop systemd[1]: blk-availability.service: Unit configuration has fatal error, unit will not be started. Aug 05 16:59:36 testlaptop systemd[1]: /lib/systemd/system/blk-availability.service:10: Neither a valid executable name nor an absolute path: ${exec_prefix}/bin/true Aug 05 16:59:36 testlaptop systemd[1]: blk-availability.service: Unit configuration has fatal error, unit will not be started. Aug 05 16:59:37 testlaptop systemd[1]: /lib/systemd/system/blk-availability.service:10: Neither a valid executable name nor an absolute path: ${exec_prefix}/bin/true Aug 05 16:59:37 testlaptop systemd[1]: blk-availability.service: Unit configuration has fatal error, unit will not be started. Aug 05 16:59:38 testlaptop systemd[1]: /lib/systemd/system/blk-availability.service:10: Neither a valid executable name nor an absolute path: ${exec_prefix}/bin/true Aug 05 16:59:38 testlaptop systemd[1]: blk-availability.service: Unit configuration has fatal error, unit will not be started. Aug 05 17:00:08 testlaptop systemd[1]: /lib/systemd/system/blk-availability.service:10: Neither a valid executable name nor an absolute path: ${exec_prefix}/bin/true Aug 05 17:00:08 testlaptop systemd[1]: blk-availability.service: Unit configuration has fatal error, unit will not be started. Aug 05 17:00:08 testlaptop systemd[1]: blk-availability.service: Cannot add dependency job, ignoring: Unit blk-availability.service has a bad unit file setting. # dpkg -l | grep lvm ii liblvm2cmd2.03:amd64 2.03.09-2 amd64 LVM2 command library ii lvm2 2.03.09-2 amd64 Linux Logical Volume Manager