ExFAT
To get ExFAT to work on Windows and Mac
1. Open up Disk Utility on Mac
2. Select your flash drive on the left side pane. Select the top-most item bearing the name of the flash drive, not any of the partitions listed below the name of the flash drive. (important)

3. Click on the "Erase" tab which is among the tabs on the top.
4. Select desired file system format using "Format" dropdown. Select exFat which works on both mac and windows, including Win10.

5. Select the desired scheme as Master Boot Record. --- this does the trick to make it detectable on windows.

6. Click "Apply"
Hope this helps.
Kim