Hello Matthias,
> I had Linux installed already on this computer and would not need to > re-partition. > > Any ideas how to fix this? Thanks for the report. This should be fixed with: 245cab2abc1fd74d1df489e500432c66c88f6b25. The issue was that the installer could not mount FAT16 partitions. Could you regenerate an installation image by running the following command: --8<---------------cut here---------------start------------->8--- ./pre-inst-env guix system image -t uncompressed-iso9660 gnu/system/install.scm --8<---------------cut here---------------end--------------->8--- and confirm that it fixes your issue? Thanks, Mathieu