GA-H170-D3HP - HDD appears MANY times in boot menu?

[Calab]

For some reason one of my hard drives is appearing MANY times in the Boot Selection menu (F12 key). This is on a GA-H170-D3HP mainboard.

This is what my boot menu currently looks like when I hit F12 at POST:


How can I clear out the duplicate entries? There are no options in the BIOS settings to remove the extra copies of the drives.

If it makes any difference, the ADATA SP550 drive has Windows 7 installed and the OCZ-Agility 3 has Mac OS X El Capitan installed. The default boot drive is the OCZ-Agility 3.

[shadowsports]

Greetings,
Power off disconnect the OCZ.  Power up, enter BIOS, reform reset, F10 to Save.  After restart, press power button until system powers off.  Disconnect power to MB, perform battery pull. 

Reconnect Drive, install battery, reconnect MB power.  Power on, <Del> to enter BIOS. Make configuration changes, F10 to save and restart.  Check F12 "one time boot menu again. 

Just my personal recommendation.  You should not rely on your BIOS, Boot Order Options, or one time boot menu to act as a boot manager for disks that contain multiple installs (different OS's), even if multiple partitions exist.  I know lots of folks do this, but its not overly reliable.