Boot Camp & External HardDrive

Windows does not install on or boot from external drives.

OK. Gotcha.

The easy solution is to partition the drive using GUID and formatting using exFAT on the Windows/Mac partition and formatting for OS X on the Mac-only partition. Do this using Disk Utility.

Drive Preparation

1. Open Disk Utility in your Utilities folder.

2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.

3. Under the Volume Scheme heading set the number of partitions from the drop down menu to two. Size each to your preference. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, set the partition scheme to GUID then click on the OK button. Click on the Partition button and wait until the process has completed.

4. Select the partition you will use on both Windows and Mac, click on the Erase tab in the DU main window. Set the Format type to exFAT, then click on the Erase button.

Do I then understand that one partition is for exclusive use by OS X while the other is for exclusive use by Windows? If so, then partition the drive using GUID, format one partition using Disk Utility to Mac OS Extended, Journaled. Format the other using exFAT. If you wish you can reformat the Windows volume to NTSF, but you will not be able to write to that volume when booted into OS X. The exFAT format provides most of the benefits of NTSF but can be written to by OS X. However, use whichever you prefer as either works with Windows.

You will have to use Windows to format that partition to NTSF since it cannot be done in OS X.

Thanks for your very clear explanations and instructions on this.