People using USB sticks or external hard drives both on MacOS and Windows operating systems might experience compatibility issues at some point. For example, you might use a USB stick on MacOS at home. Then you might try to use the stick later on a Windows machine at the office, but can’t open it and you might be asked to re-format it.
I often have to use my flash drive (I really enjoy Corsair Survivor USB 3.0) or external HDD with large files, both on MacOS and Windows. After experiencing several similar issues as in example, I found simple solution.
While Windows works with NTFS and FAT filesystems, MacOS uses HFS+ (but is friendly with FAT filesystem too). Usually, a flash drive or external HDD used mostly on Windows is formatted in NTFS format which can’t be written by MacOS (It only can read it). Drives formatted for use on MacOS usually will have HFS+ filesystem, causing similar issues when opening on Windows.
There is paid third party software called “Paragon NTFS”, which helps you write on NTFS drives using Mac OS (Seagate offers free download of it for their drives). Also, there are third party drivers. Apple has its own, experimental support for writing on NTFS drives. But, all of them are complex solutions and are going to work only on single configured Mac.
The common ground for both Windows and MacOS is the FAT filesystem. Note that if you are going to use files larger than 4GB (it’s the size limit per file for FAT32) you need to use an extended FAT, shortly exFAT.
It’s better to use exFAT anyways.
So the simplest solution for USB stick or external HDD incompatibility between MacOS and Windows, is formatting the drive in extFAT format. You always have that option when formatting a drive on both operating systems.
WARNING: formatting the drive (both flash and external HDD) erases all the data on the drive and it cannot be restored in most cases. Back-up valuable data before formatting your drive.
Note: If you want to use your external drive for Time Machine, it has to be on HFS+ filesystem and can’t be using exFAT.
For MacOS users:
For Windows users:
Once formatting is done, the drive should work both on MacOS and Windows.