I have a Roku tv, and I can play movies from my external USB drive with no problem. I have a Samsung tv with a Roku dongle, and that one keeps asking me to format the drive. Why will it work on one but not the other?
By "Roku dongle" I assume you mean a Roku Stick, which connects directly to the HDMI port without a cable. The Stick has no external USB port, and does not support connecting a USB hub to the power port. That means you're connecting the USB stick directly to the Samsung TV via USB. So the second Roku is meaningless.
If you have one device (the Roku TV) that can play a video but another device (the Samsung) cannot, then the problem is with the Samsung. Since you are getting a message about formatting the drive, that indicates your USB drive is not formatted with a file system the TV recognizes.
You can see the lists don't match up, so your USB drive is likely formatted in a file system that Roku supports but Samsung does not.
Apparently the Samsung TV is more limited as to what drives it will play. Probably the (unspecified) volume/disk format is the limiting factor for the Samsung.
I assume you are plugging the drive into the Samsung TV - and not involving the Roku in any way.
