Boost.Python error in job “umount”.
<class ‘OSError’>
[Errno 39] Directory not empty: ‘/tmp/calamares-root-5ymwoaa2’
Traceback:
File “/usr/lib/calamares/modules/umount/main.py”, line 105, in run
os.rmdir(root_mount_point)
System is a Dell Latitude 5401 with Intel I7 9850H, 32GB RAM, 512 NVMe SSD and Intel UHD 630 graphics.
Welcome! 
Was it offline or online installation, or you couldn’t even boot Calamares further than that choice?
Welcome!
I’ve found Calamares can fall over if you’re trying to install to pre-determined partitions. I’ll generally clear the drive I’m installing to of any partitions at all, and let Calamares do it all during installation, which normally works fine then.
It was the online installer, all defaults except swap with hybernate selected
What file system?
Can you try offline one with same settings?
you need to reboot to LiveSession if you chancel installation, it can cause issue like this.
And clear partition you want to use before is also helpful in case there was another Linux installed before.
Go with GParted from the Live ISO to partition your disk before to launch Calamares would resolve it.
This saved my bottom, thank you!
This might be the problem I was having on an older laptop.