- In order for an external drive (hard drive and flash drive) to work with both Windows and MacOS, it has to be formatted with the exFAT file system.
***Formatting a drive means you will lose ALL data on that drive. Make sure all of your data is backed up BEFORE your format the drive***
Open Finder, go to Applications > Utilities > Disk Utility
Select [hd:DriveName], then Erase *Use caution not to select the Macintosh drive
Name the drive, then change the Format to exFAT
On Windows 10:
Go to File Explorer > This PC
Right click on [hd:DriveName], then Format *Use caution not to select the C: drive
Change File System to exFAT and name the drive under Volume Label
*Optional: If you believe the drive is experiencing issues, uncheck Quick Format which will scan the drive for errors. Otherwise, keep Quick Format checked.