If the device contains any files you want to save copy them to another storage device or volume.
Lock usb drive mac.
In the disk utility app on your mac choose view show all devices.
One option is to fully encrypt the external drive and lock it with password.
If you do not see the encryption option in the drop down menu your usb flash drive has not been formatted using the guid partition map.
The best part about this application is that it s available for both windows and macos devices.
In the sidebar select the storage device you want to.
Set up usb lock on pc or mac rohos key logon is a software that can program a usb flash drive a mobile phone or even a bluetooth device to act as the key to unlock your system.
In the filevault window you can set a password by typing it in twice as well as set a password hint.
When you see your removable disk in the left panel right click it and select encrypt from the contextual menu.
Insert your usb drive into the mac and open a finder window.
Encrypt external hard drive on mac.
Connect the usb flash drive to your mac and find its disk icon on the desktop or finder sidebar then right click and select encrypt usb stick name from the context menu.
Fortunately mac os x provides a few native solutions to help you protect your data on external hard drives.