Unlike Windows OS, Mac OS doesn't provide quick format tool. Two Reliable Disk Formatting Software for Mac
Here are two hard drive format software tools for Mac to help you securely format, reformat and erase hard drive, external hard drive, USB flash drive, and memory card under Mac OS. But, how to format a local/external hard drive under Mac OS? How to format a hard drive on Mac and permanently erase the data information on the hard drive? Don't worry. Normally, once your hard drive is formatted, you will get a brand new hard disk drive. Formatting is the easy solution to help you remove all data/traces on your Mac hard drive. You may want to get rid of all this junk data and reuse your hard drive. After years of use, thousands of files and GBs of file fragments have been stored on your Mac hard drive.