I've upgraded ever since Gutsy: to Hardy, Intrepid and Jaunty. But this time, I did a fresh install of Karmic Koala, given the new Grub, ext4 and so on. Here are some things (bugs I mean - with potential fixes) I've experienced running Ubuntu Karmic Koala as my main OS (for about 2 days now):
1. I installed it, rebooted and got some inconsistency error on my HDD ("Unexpected Inconsistency: Run Fsck Manually"), for both the / and /home partitions. After I did "fsck /dev/sda1" and "fsck /dev/sda5", I managed to boot into Ubuntu Karmic Koala. I have 3 hard disks of which 2 are kind of old, but this was my somewhat new hard disk and I really didn't expect it to fail. After a bit of googleing, it turns out it's not something wrong with my hard disk, but some bug in Karmic:
The error that the OP posted is a clock error. Basically what I think is happening is that the hardware clock is behind the local time, and it's not loading the local time before it does the filesystem check. The filesystem is labeled with its last write time, which of course is the local time, so it looks like the filesystem was mounted in the future to the operating system.
More details about this, here.
2. I have an DSL internet connection which