I upgraded from Ubuntu 12.10 to 13.04. I have got an error massage before the upgrade was finished and now i have the feeling that Ubuntu 13.04 was not installed correctly. How can i check/scan the OS for errors ? I dual boot with Windows 7.
To be honest I'm not aware of any utility to scan for installation errors, but if you are experiencing some weird behaviour from the OS, you could try to reinstall the
ubuntu-desktop metapackage, it should reinstall everything that may be lost/damaged during the upgrade.
I'm using Kubuntu, and sometimes when I get problems in updating the files of the KDE environment, reinstalling
kubuntu-desktop (which, as you can guess, is the equivalent to
ubuntu-desktop for Kubuntu) solves anything.
Anyway, from a more general point of view, I found that when making major version upgrades, it is better to use a LiveCD, rather than using the built-in upgrade options, it causes far less problems; if you have your /home folder on a separate partition, you won't lose any data, and you simply have to reinstall some software.