I have a VirtualBox machine running Lubuntu 15.04 with an excessively slow boot time (1:30+). It does not have the VirtualBox guest additions installed.
The problem started when I had completely run out of virtual space on the VM. I used VBoxManage <VDI file> --resize <10 GB> to resize the disk, and then used a gparted live cd to reconfigure the partitions. I set it up such that there were only two partitions(/dev/sda1 and /dev/sda2 respectively), with the first being an ext4 filesystem, and the second being a 1GiB linux-swap partition.
After that, the VM would boot correctly, but very slow.

The problem is that it is waiting for the timer to hit 1:30 to continue booting.
What does the message mean and how do I fix it?
For future readers: I solved this problem by running the below procedures:
sudo mkswap /dev/sda2(this outputs a new UUID)sudo swapon /dev/sda2sudo leafpad /etc/fstab- Replace the swap UUID with the new one
sudo update-grub(ensure no old UUIDs are laying around)