You cannot move existing recordings or recording schedules from legacy network-connected or TV-connected Tablo devices to the 4th Generation Tablo DVR.
Formatting a drive erases the contents of said drive.
For instructions on how to add an external hard drive to a legacy Tablo DVR, go here.
The 4th Generation Tablo comes with 50+ hours of onboard recording storage. This means you can watch Live TV or schedule recordings without connecting an external hard drive. However, you can expand the recording storage of the 4th Gen Tablo at any time by connecting a compatible USB hard drive.
If/when you attach an external storage device, you will still be able to play and delete recordings on the internal storage but all new recordings will be sent to external storage.
How to Add a Hard Drive to the 4th Generation Tablo
To expand the recording capacity of the 4th Generation Tablo, simply connect a portable USB hard drive, between 1 TB - 8 TB, to the Tablo's USB port.
If your Tablo has already been set up, you will see a prompt to format the drive within the Settings screen of the Tablo app in the Storage section. Follow the on-screen instructions to format the drive for Tablo's use.
If your Tablo has not yet been set up, please do so first before connecting a hard drive. Once your Tablo has been set up you can format your new hard drive from the Settings screen as described above.
For instructions on setting up your Tablo via iOS, go here.
For instructions on setting up your Tablo via Android, go here.
Why You May Wish To Use External Storage With the 4th Generation Tablo
When using onboard storage on your 4th Generation Tablo, recordings of over-the-air content will first be saved in MPEG-2 video format but later undergo an archiving process which will transcode the video into MPEG4 to save space while preserving as much video quality as possible.
All recordings of free ad-supported streaming channels will be in MPEG-4 regardless of the storage type used.
External drives keep your recordings in their original MPEG2 format, saving time by removing the compressing to MPEG-4 process. The difference is especially noticeable with long, 8+ hours, recordings. As such, adding a USB hard drive to your 4th Generation Tablo is recommended.
For more details go here.