With MacDrive installed, you may be prompted that "MacDrive has protected a Mac disk - Windows can't modify partitions on Mac disks". MacDrive automatically protects Mac disks from being modified by Windows in order to protect data on the disk.
Letting Windows modifying Mac partitions or otherwise change the structure of a Mac disk is risky. Because Windows isn't designed to safely modify Mac disks, it's possible that changing just one partition on a Mac disk may cause other partitions on the disk to disappear, resulting in data loss. This dialog box also prevents accidentally formatting the Mac disk when it's not intended.
When you see the MacDrive disk protection dialog box, you'll have three choices:
Don't change the Mac disk: You should choose this option if you did not intend to erase or modify your Mac drive, such as if this message occurs unexpectedly.
Modify the Mac disk with MacDrive Disk Manager: MacDrive can safely add or remove individual partitions from a Mac disk without affecting other Mac partitions. You should select this option if you want to keep the disk Mac-formatted, but you want to make changes to one or more individual partitions.
Erase the Mac disk so I can make Windows partitions: You should select this option if you no longer want the disk to be Mac-formatted, and want to use Windows to format it permanently and start over (such as to NTFS or FAT32).
Please note that MacDrive does not support disks with multiple partition types other than those created on a Mac with Boot Camp, so it's not possible to use MacDrive to create a disk with both Mac and Windows partitions.