This is not because of the reason Colin said, but relates to it.
It's caused by the wrong way grub responds to the proprietary software, not the proprietary software itself.
To avoid the sectors stolen, grub mistakenly overwrites sectors of the first partition.
The dd thing Colin mentioned won't work because it only overwrites the mbr and the embedding area, the ntfs itself will still remain corrupted.
This is a duplicate of /bugs.launchpad .net/ubuntu/ +source/ grub2/+ bug/730225
https:/
This is not because of the reason Colin said, but relates to it.
It's caused by the wrong way grub responds to the proprietary software, not the proprietary software itself.
To avoid the sectors stolen, grub mistakenly overwrites sectors of the first partition.
The dd thing Colin mentioned won't work because it only overwrites the mbr and the embedding area, the ntfs itself will still remain corrupted.