"Could not display" dialog is rough
This was originally reported as part of GVFS issue 17. I was told that it's a Nautilus issue, so here I am.
The dialog in question looks like this. Various issues with this:
The title doesn't use header capitalisation
There's a full stop at the end of the heading
The line break in the description looks odd and probably isn't necessary
The "No" and "Yes" buttons aren't instructive - you need to read the description to find out what they do. "Cancel" and "Search in Software" might be better labels
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information