If Grub2 is already installed on your system:
* keep the current version of grub rather than choose the maintainer's version.
* if you manually install Grub take care not to install grub to the Windows partition. In that case Windows will fail to start.
As from this thread in the german ubuntu forum: forum.ubuntuuse rs.de/topic/ windows- 7-bootet- nach-ubuntu- update- nicht/
http://
there is evidence that this is not really a bug from grub but from the way the installer performs the upgrade.
If Grub2 is already installed on your system:
* keep the current version of grub rather than choose the maintainer's version.
* if you manually install Grub take care not to install grub to the Windows partition. In that case Windows will fail to start.