The directory is 100% full. Is there any way to do this without using a bootable USB drive?
As you can see from the above image of GParted the drive does have some free unallocated space.
or alternatively make room in the directory. My /home directory is already mounted on a different drive.
I am also dual booting Windows 11 and it is installed on the same drive. It shouldn't cause any issues though.
Is there any way to expand root without using a bootable USB drive? Yes there is. See my question and answer here. How to modify partitions without a live USB/CD This approach would allow you to make use of the unallocated 8GiB immediately before your root partition by moving it and then expanding it with GParted. This is the only method that gives you access to the 8GiB.
There is an alternative however if you are prepared to shrink /dev/nvme0n1p5 slightly and use the space released in your root partition. To do that you need a windows app like Minitool wizard (link here. https://www.partitionwizard.com/ ) Using that app you would shrink nvme0n1p5 and then move it to the end of the drive (to the right). Once you have done that go back into Ubuntu and follow the answer here. How can I resize an ext root partition at runtime? You need to use the growpart and resize2fs commands as described in that answer.
A word of caution, operations on partitions can go wrong so make sure you backup any data you cannot afford to lose.
Good luck
