Information of the issue:
This post provides info and solutions to resolve an issue Mac users will encounter when using disks formatted on Mac OS X which will be connected to Mede8er X3D series media players (as of this time version 3.0.4). Basically what is witnessed when two disks are connected to the Mede8er X3D series media player, is that two empty Fat32 volumes (which should be invisible) will be mounted, as well as the volumes containing the media on each disk. The issue here is that the Mede8er X3D series media players shouldn't mount the two Fat32 partitions. The result to the user is that the media will appear not on the volume as expected but on the other volume. For example, if USB disk 1 is named TV, and USB disk 2 is named Movies, the user will see the TV programmes on the Movies disk and the Movies on the TV Programmes disk. The Mede8er X3D is seemingly confused due to it mounting these blank Fat32 partitions.
Legacy Windows systems use the BIOS and must use a Master Boot Record (MBR) partition scheme with an NTFS format, these are not affected. Disks with a MBR partition scheme with an ExFAT format are also not affected. Windows will create disks of these configurations by default.
By default, Disk Utility in Mac OS X will erase and format a disk as a Mac OS Extended Journaled (HFS+) format with a Globally Unique Identifier Partition Scheme A.K.A GUID or GPT. This is used for bootable or non-bootable disks (external storage) to be used with Mac OS X, or as external non bootable storage for other systems with HFS+ drivers. This GPT partition scheme creates a 209MB Fat32 partition for booting EFI capable machines, such as Intel based Mac's, UEFI based Windows 8+ 64 bit machines (non BIOS), and many Unix (BSD, Linux), UEFI systems. This Fat32 partition is hidden in Mac OS X Disk Utility and is not mounted. It can be shown when Disk Utilities Debug menu is enabled. It will be shown as the BSD identifier such as 'disk2s1' in Mac OS X 10.6.x. In Mac OS X 10.9 (possibly even 10.7 & 10.8) , it is shown as 'EFI' and again, it isn't mounted.
For users of Mac OS X machines the EFI partition on these GPT disks will need to be removed so that the Mede8er X3D can behave properly so that disks are mounted as expected. This can be done in two different ways, one, using the graphical user interface, and two, for those who prefer a faster method, via the Terminal. I'll explain both methods and provide images to give a visual reference.
Note, this does not delete or erase any of your media data on the main partition, so no need to backup and copy back.Graphical user interface method. This requires one terminal command to make the EFI Fat32 partitions visible.
1. Launch Terminal.app, located at /Applications/Utilities/Terminal.app. We want Disk Utility show the debug menu which contains a menu option to show hidden disk partitions, so copy & paste this command into the Terminal and hit the enter key:
defaults write com.apple.DiskUtility DUDebugMenuEnabled 1
You can quit the Terminal now.
2. Launch Disk Utility, located at /Applications/Utilities/Disk Utility
Click the Debug menu and select 'Show every partition'. You'll notice some greyed out partitions under the connected disks in the sidebar, it's greyed to signify it isn't mounted.
3. Click on the greyed out partition under the external disk we want to work on. It will show either the BSD disk identifier such as disk2s1 as in my images from Mac OS X 10.6.8 or 'EFI' if on 10.9, maybe even 10.7 & 10.8.
Click the 'Erase' Tab then click the 'Erase' button. You'll notice after this, the partition becomes mounted and the text is the normal shade of grey.
4. Now select the actual external disk in the sidebar which is on top of the partitions shown below it. You'll notice there is now a 'Partition' tab, click it. Under Volume Scheme, a visual reference of the partition is shown. Click the first small partition so it's highlighted, this is the one that was erased and mounted in previous steps. Then click the Remove button (minus icon).
5. Click the 'Remove' button from the drop down sheet. After this, the 'disk2s1' or 'EFI' partition will no longer be shown, in the sidebar, it's gone and only the main large volume containing your media files shall remain.
Final visual reference of Disk Utility after the removal of the EFI partition. Now eject the disk and plug into the Mede8er and the issue is resolved.
===============================================================================Command line method, way faster.
Terminal commands to delete EFI Partition (in this case, it's disk2)
To show a list of the disks, type or copy & paste to Terminal and hit enter:
Identify disk with EFI partition (it's never disk0 this is internal), type or copy & paste to terminal and hit enter:
diskutil unmountDisk /dev/disk2
To remove the EFI partition, type or copy & paste to Terminal and hit enter:
sudo gpt remove -i 1 disk2
It asks for password, type in your admin password and hit enter. The terminal will show a confirmation of execution.
Sample image for reference: