Comment 28 for bug 570765

+1 for Jeff.

I do not know how ubiquity work but AFAIK I see 3 solutions here (sort by expected difficulty):

- release a 0 day upgrade (dummy if necessary) that will force grub to update → bad because the iso is buggy, the user may be afraid on the first reboot and all users can't update their OS whenever they want.

- disable migration-assistant by default (because the bug is likely to came from here and it seems to be buggy anyway, see bugs #536673 and #220064) → bad because this is also a feature for some users...

- find and apply a proper fix → may request some time...

perhaps number 2 is the less bad in this situation ?