Installer pkg file name changes: a follow-up

Last week, we reported that changing the name of an Installer .pkg file in any way prevents the file from opening correctly in the Installer utility (e.g., the splash screen does not appear). We speculated on what the exact cause of this glitch might be. Our own research, combined with the helpful suggestions from several MacFixIt readers, has given us at least most of the answer:

If you use the Show Package Contents contextual menu command to delve into the contents of a installer pkg file, you will eventually locate files that have the same name as the pkg file itself, except with a different extension. For example, in the Contents/Resources folder, you might find: filename.sizes, filename.bom, filename.pax, and possibly others. Inside the Contents/Resources/English.lproj folder will also be a file called filename.info. If you change the name of the enclosing pkg file, you will get an error when launching the file unless almost every one of these similarly named files is also changed to match. When we tested this, we found: the name of the pax file did not have to match; changing the name of the bom file led to a different type of error (a message that said "Missing or old bill of materials"). Otherwise, unless all names matched, you got the splash-screen-failure-to-appear error.

Application (.app) packages do not have this same limitation. It appears to be a specific interaction between Installer pkg files and the Installer utility itself. Perhaps Apple will address this in an update to the Installer utility.

(Thanks, Scott Boone, Bill Bumgarner, Doug Brown, and others.)