package mdadm 3.3-2ubuntu7.2 failed to install/upgrade: subprocess installed post-removal script returned error exit status 127

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ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: mdadm 3.3-2ubuntu7.2
ProcVersionSignature: Ubuntu 4.4.0-78.99-generic 4.4.62
Uname: Linux 4.4.0-78-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.1-0ubuntu2.10
Architecture: amd64
Date: Thu Aug 10 21:13:23 2017
DpkgTerminalLog:
 Removing mdadm (3.3-2ubuntu7.2) ...
 /var/lib/dpkg/info/mdadm.postrm: 10: /var/lib/dpkg/info/mdadm.postrm: update-initramfs: not found
 dpkg: error processing package mdadm (--remove):
  subprocess installed post-removal script returned error exit status 127
DuplicateSignature:
 package:mdadm:3.3-2ubuntu7.2
 Removing mdadm (3.3-2ubuntu7.2) ...
 /var/lib/dpkg/info/mdadm.postrm: 10: /var/lib/dpkg/info/mdadm.postrm: update-initramfs: not found
 dpkg: error processing package mdadm (--remove):
  subprocess installed post-removal script returned error exit status 127
ErrorMessage: subprocess installed post-removal script returned error exit status 127
InstallationDate: Installed on 2015-01-27 (925 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.2
 apt 1.2.24
SourcePackage: mdadm
Title: package mdadm 3.3-2ubuntu7.2 failed to install/upgrade: subprocess installed post-removal script returned error exit status 127
UpgradeStatus: No upgrade log present (probably fresh install)