Just for the sake of alternatives, a long standing linux utility kdiff3 that is also available for Windows https://download.kde.org/stable/kdiff3/?C=M;O=D
..not very pretty but it does work. Would I recommend it for sync-ing, probably not (edit: I dont think it does anyway for a USB drive), but it will compare the contents of folders and does recurse sub-folders. As with anything, set up in preferences, the default is a binary compare which takes forever.
A quick 40 second example: Windows 10 https://i.imgur.com/WiNQH8m.mp4 a couple of files missing and a whole sub-folder.
..not very pretty but it does work. Would I recommend it for sync-ing, probably not (edit: I dont think it does anyway for a USB drive), but it will compare the contents of folders and does recurse sub-folders. As with anything, set up in preferences, the default is a binary compare which takes forever.
A quick 40 second example: Windows 10 https://i.imgur.com/WiNQH8m.mp4 a couple of files missing and a whole sub-folder.