package caribou-antler 0.4.20-1 failed to install/upgrade: subprocess installed pre-removal script returned error exit status 1

crashes on logout

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: caribou-antler 0.4.20-1
ProcVersionSignature: Ubuntu 4.4.0-46.67-generic 4.4.24
Uname: Linux 4.4.0-46-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
Date: Fri Aug 10 08:24:13 2018
DistributionChannelDescriptor:
 # This is a distribution channel descriptor
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-xenial-amd64-20160624-2
ErrorMessage: subprocess installed pre-removal script returned error exit status 1
InstallationDate: Installed on 2017-11-10 (272 days ago)
InstallationMedia: Ubuntu 16.04 "Xenial" - Build amd64 LIVE Binary 20160624-10:47
PackageArchitecture: all
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1
 apt 1.2.10ubuntu1
SourcePackage: caribou
Title: package caribou-antler 0.4.20-1 failed to install/upgrade: subprocess installed pre-removal script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)