If you have recovery partitions which were created by the OEM, then they can cause problems. If you are imaging computers with FOG, you don’t want the recovery partition in most cases. You can’t easily remove it because they try to make it idiot proof and allowing users to delete the recovery partition makes it useless.
I have a bunch of Fujitsu laptops that shipped with the recovery partition and rather than reload Windows 7 from scratch, I used a USB flash drive with GParted to remove the recovery partition and resize/rearrange the rest.