package mdadm 3.3-2ubuntu7.6 failed to install/upgrade: subprocess installed post-installation script returned error exit status 20

Unable to upgrade or reinstall mdadm

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: mdadm 3.3-2ubuntu7.6
ProcVersionSignature: Ubuntu 4.4.0-133.159-generic 4.4.134
Uname: Linux 4.4.0-133-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.18
Architecture: amd64
Date: Thu Aug 23 23:33:15 2018
DuplicateSignature:
 package:mdadm:3.3-2ubuntu7.6
 Setting up mdadm (3.3-2ubuntu7.6) ...
 dpkg: error processing package mdadm (--configure):
  subprocess installed post-installation script returned error exit status 20
ErrorMessage: subprocess installed post-installation script returned error exit status 20
InstallationDate: Installed on 2016-05-30 (815 days ago)
InstallationMedia: Ubuntu-Server 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.3)
MDadmExamine.dev.sda:
 /dev/sda:
    MBR Magic : aa55
 Partition[0] : 29294592 sectors at 2048 (type 83)
 Partition[1] : 205142018 sectors at 29298686 (type 05)
MDadmExamine.dev.sda1: Error: command ['/sbin/mdadm', '-E', '/dev/sda1'] failed with exit code 1: mdadm: No md superblock detected on /dev/sda1.
MDadmExamine.dev.sda2:
 /dev/sda2:
    MBR Magic : aa55
 Partition[0] : 197263360 sectors at 2 (type 83)
 Partition[1] : 7878656 sectors at 197263362 (type 05)
MDadmExamine.dev.sda5: Error: command ['/sbin/mdadm', '-E', '/dev/sda5'] failed with exit code 1: mdadm: No md superblock detected on /dev/sda5.
MDadmExamine.dev.sda6: Error: command ['/sbin/mdadm', '-E', '/dev/sda6'] failed with exit code 1: mdadm: No md superblock detected on /dev/sda6.
MDadmExamine.dev.sdb:
 /dev/sdb:
    MBR Magic : aa55
 Partition[0] : 3907029167 sectors at 1 (type ee)
MDadmExamine.dev.sdc:
 /dev/sdc:
    MBR Magic : aa55
 Partition[0] : 4294967295 sectors at 1 (type ee)
MDadmExamine.dev.sdc2: Error: command ['/sbin/mdadm', '-E', '/dev/sdc2'] failed with exit code 1: mdadm: No md superblock detected on /dev/sdc2.
MachineType: To Be Filled By O.E.M. To Be Filled By O.E.M.
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-133-generic root=UUID=b0849eae-81cb-4a51-95b4-f8f347bf7197 ro text
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.4
 apt 1.2.27
SourcePackage: mdadm
Title: package mdadm 3.3-2ubuntu7.6 failed to install/upgrade: subprocess installed post-installation script returned error exit status 20
UpgradeStatus: Upgraded to xenial on 2018-08-23 (0 days ago)
dmi.bios.date: 04/29/2015
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P1.50
dmi.board.name: AM1H-ITX
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP1.50:bd04/29/2015:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnAM1H-ITX:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.name: To Be Filled By O.E.M.
dmi.product.version: To Be Filled By O.E.M.
dmi.sys.vendor: To Be Filled By O.E.M.
etc.blkid.tab: Error: [Errno 2] No such file or directory: '/etc/blkid.tab'