Computer freezes ~1 minute after booting 16.04 with 4.4.0-22

I recently upgraded from Ubuntu 14.04 LTS to 16.04 LTS. Bootup with 4.4.0-22 takes ~2 minutes to get to desktop, then operates very slowly for about a minute before freezing. Need to shut off power and reboot. Numerous attempts all ended with freeze-up. However, booting with 3.13.0-86 takes about 50 secs to get to desktop and everything operates smoothly.
Bill

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubuntu-release-upgrader-core 1:16.04.14
ProcVersionSignature: Ubuntu 3.13.0-86.131-generic 3.13.11-ckt39
Uname: Linux 3.13.0-86-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Wed May 18 12:51:28 2016
InstallationDate: Installed on 2014-10-17 (579 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: release-upgrade
UpgradeStatus: No upgrade log present (probably fresh install)
VarLogDistupgradeAptlog:
 Log time: 2016-05-18 10:59:15.242903
 Starting pkgProblemResolver with broken count: 0
 Starting 2 pkgProblemResolver with broken count: 0
 Done
 Log time: 2016-05-18 11:00:16.155145