A few nights ago I was working on a personal AIR project and wanted to include an icon with it. This was - so I thought - rather easy. I found a nice icon, saved it into an assets folder, and then edited mything-app.xml:

Generating the AIR file though threw an odd error:

Um, yeah, that's nice and verbose, thanks. After some googling I knew it was icon related (and could confirm by rolling back my change to the XML file), but I couldn't figure out what was wrong. I tried moving the icon around, and tried different paths, but nothing worked.

Finally, Mike Chambers helped me out and pointed out the issue. Turns out when I have picked an icon I had only set a 128x128 icon. I was too lazy to resize the icon. Well AIR didn't like that. It thought I had specified icons for all sizes, but had used blank values for the other three sizes. This is what made AIR throw a fit. Personally I think that's a bit silly. If the value exists, but is blank, it should be treated like a null, but whatever. It was certainly non obvious to me, and I appreciate Mike helping me out. The fix I used (at first, I did end up making smaller sized icons) was to simply surround the 3 XML entries for the other icons with a comment:

Woot. That made it build. I did end up with an issue with my 48x48 icon. Maybe I resized my graphic wrong, but I ended up not being able to build until I kept that one commented out, but I figure supporting 3 of the 4 sizes is enough for an application that will have a grand total of one user.