15.04 - very slow boot

I had the same error - it was related to the UUIDs in /etc/fstab. I had resized the disk partition, by deleting the swap partition, and then recreating swap. This caused the swap UUID to change.

List the UUIDs with:

 sudo blkid

And then check/fix any thatdo not match

 sudo vi /etc/fstab

On the released version 15.04. I resized the partition, and after that things really slowed down.

 10.588140] audit: type=1400 audit(1430119499.379:11): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/bin/evince-previewer" pid=370 comm="apparmor_parser"
 [   97.136477] cgroup: new mount options do not match the existing superblock, will be ignored
 [   97.420519] vboxsf: Successfully loaded version 4.3.26_Ubuntu (interface 0x00010004)
 [   97.421318] cfg80211: Calling CRDA to update world regulatory domain
 [   97.436569] cfg80211: World regulatory domain updated:

The problem was caused by bad swap partition reference in /etc/crypttab. It waited 90 seconds before giving up on that. For some reason swap was defined on an non-existing drive, once the line was deleted, everything works fine.