Comment 13 for bug 249340

I just want to mention a possible important aspect:
This bug is not limited to OS Upgrades!

I tried adding another language via System->Administration->Language Support, and got the exact same issue: hang when generating locales.

The "work around" that made my machine able to install stuff was:
1) reboot (the only way to kill locale-gen)
2) sudo rm /usr/bin/localedef (deletes all localization)
3) sudo dpkg --configure -a ("fixes" the package manager so u can install stuff)

However, when I tried to re-install "locales" and "belocs-locales-bin" using the synaptic package manager, i got into the same problem; hang when generating locales.

I hope this will help to track down the bug, since this is not only an upgrade issue, the simplest steps to reproduce are:
1) Open language Support (System->Administration->Language Support)
2) Select another language
3) Click OK
4) Notice the system hang when generating locales