That’s showing the first partition (volume) (/dev/sda1) is unmounted. Since you are booted into Ubuntu, /dev/sda2 will be mounted.
Just as a side note, /dev/sda referrs to the while drive, whereas /dev/sda1 and /dev/sda2 refer to the individual partitions on the drive. The system prevents unmounting the whole drive while a partition/volume is mounted and in use.
If you click on the second large Partition 2 space, you will likely see that it is in use.