If you use external drives frequently with your Mac, The Alice Dev Team' USBMate is an inexpensive tool for optimizing your file storage system and more. It requires macOS 10.6 or higher and is available worldwide through the Mac App Store in the Utilities category.
Featuring a file storage system optimization, USBMate was developed specifically to use for USB Flash drives, external hard disks and Flash memory cards. It lets you erase temporary files left by the Mac’s operating system — even Windows. What's more, USBMate also sports an anti-virus program.
Normally, when you erase files, they're only moved to the trash. The data itself isn't erased. Use USBMate before ejecting an external drive and it erases all temporary files (.DS_Store, .Trashes, .Spotlight-V100, Thumbs.db, etc.) left by the previously-mentioned operating systems, and shows how much free space is still available.
What's more, each time the app is launched (and you can set it to start at log-in), the anti-virus automatically checks and purges the USB Flash drive’s contents of all AutoRun viruses. USBMate is a breeze to use; once installed, you access it via a small icon in the Mac toolbar.
USBMate is a practical utility for everyday use. Especially if, like many of us, you find yourself dealing with an increasing number of external drives. The latest version (1.1) fixes some bugs and adds support for large capacity, external USB drives.