If you've been considering buying a brand new 3TB or 4TB external hard drive to plug into your TV's USB port for media playback, you might want to reconsider. New drives that use such large capacities usually also rely on a partitioning format called GPT (GUID Partiton table), which allows the entire capacity of the drive to be usable on a computer system.
However, that same partitioning format may not be recognised by your TV — we recently found this out when we plugged in a 3TB WD Elements hard drive into a 32in Samsung LA32C450E1D LCD TV. If you plug a GPT-based drive into a TV, it might show up as being recognised by the TV, but it will not be able to display any of the information that you may have previously put onto it.
The solution is a harsh one: you'll have to re-partition the drive so that it uses an MBR (Master Boot Record) partition instead. This is not an ideal solution because it means that only up to 2TB of space will be usable on a 3TB or 4TB hard drive. This space will be wasted, but at least now there will be a chance that your new drive will be detected and read by your TV.
All data on the disk will be erased if you attempt to change the drive's partition type from GPT to MBR, so you should make sure that you have a copy of all your data on another drive prior to changing it. To change the partition type under Windows 7, you will have to launch the disk manager (go there by right-clicking Computer from the Start menu, selecting Manage and then Disk Management), right-click on the drive's label and convert it to MBR. You can then create a partiton and format it using the NTFS file format.
If your TV does not support the NTFS file format, but prefers the Fat32 format instead, then you will have to download a third party utility to convert your NTFS drive to Fat32 — Windows 7 can not do this (not successfully in our experience anyway). The utility that has worked well for us is Fat32format. It's a relatively straightforward utility to use: select the correct drive that you wish to format (double-check to make sure that you have the right one), leave the file allocation unit size of 32768 bytes (as you'll be storing large media files on it rather than tiny files), and click the start button. It will only take a few seconds to format.
This isn't an ideal solution for a 3TB or 4TB drive, but it's a necessary one for the moment if you have bought one of these drives for the primary purpose of using them as a media repository for a TV. If you are currently shopping for a hard drive that can be used to play media through your TV's USB port, stick to drives that are less than 2TB in size, otherwise space will be wasted if you need to convert the drive's format.