Upgrading 12.04 LTS to 14.04 LTS

[Robert Cahn]

Part way through the install it says it can't calculate the amount of space needed and bombs out. I'm stuck at 12.04 unless I wipe the disk.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.17
ProcVersionSignature: Ubuntu 3.2.0-70.105-generic 3.2.63
Uname: Linux 3.2.0-70-generic i686
ApportVersion: 2.0.1-0ubuntu17.8
Architecture: i386
Date: Sat Nov 15 16:59:53 2014
EcryptfsInUse: Yes
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1416087766
 com.ubuntu.update-manager window-height 676
 com.ubuntu.update-manager window-width 600
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-11-15 (0 days ago)
VarLogDistupgradeTermlog: