1- WARNING! THIS WILL ERASE YOUR DISK >>> (sdb, 2TB)

    fdisk /dev/sdb

first, you need to delete. press d. 
then,
press n, select primary (press p), select space number (select 1), enter, +1.9T enter. press w

2-

    mkfs --type ext4 /dev/sdb1

if you get any error at this stage, you need to control file system

    file -s /dev/sdb1

if there is a filesystem for sdb1, you have to delete it. after deleting it, run the mkfs command

    wipefs -a /dev/sdb1

3-

    mkdir /media/2TB1

4-a (temp way, you will have to do this after your new logins)

    mount /dev/sdb1 /media/2TB1

5-b (perm way. do just once)

    sudo nano /etc/fstab
add this line to the file, then press ctrl+O and ctrl+x

    /dev/sdb1 /media/2TB1 ext4 defaults 0 0

type

    mount -a


now, you can use your 2TB disk in ubuntu. if your aim is not formatting your disk, please let me know. we may road another way for you.