Ubuntu 16.04 - Loading libc6-udeb failed for unknown reasons. Aborting.

Well there’s a bummer. You go to run an unattended install on new hardware, that has worked hundreds of times before, and you get this cryptic message:

‘Loading libc6-udeb failed for unknown reasons. Aborting’

Great! 😒

TL;DR

Your installer is out of date; update it and all will be golden. http://archive.ubuntu.com/ubuntu/dists/xenial-updates/main/installer-amd64/current/images/netboot/

Continued

If you have also received this message whilst trying to netboot a Ubuntu 16.04 installation, from either the mini.iso or a PXE environment, you may have also encountered this message:

‘An installation step failed. you can try to run the failing item The failing step is: Detect disks’

Which, if like me, you may have wasted an hour or two trying to figure out if there was an issue with your hardware 🤔

What went wrong

Well I don’t know exactly, but I found a post on the Debain bug mailing list by Alex Brett (Citrix), who pointed out that the out of date installer is not compatible with the latest libc6-udeb that is received from the xenial-updates apt repo on install.

Thanks, Alex! 🙌

Fixing it

If you are using the mini.iso, go and download a new version of it - http://archive.ubuntu.com/ubuntu/dists/xenial-updates/main/installer-amd64/current/images/netboot/mini.iso

Or, if you are using PXE, then you’ll want this - http://archive.ubuntu.com/ubuntu/dists/xenial-updates/main/installer-amd64/current/images/netboot/netboot.tar.gz

All other files and architectures can be found in the xenial-updates root directory - http://archive.ubuntu.com/ubuntu/dists/xenial-updates/main/