How does OSX tell what app to open when you double click a file?

Paul Dupuis paul at
Tue Aug 6 16:36:40 EDT 2019

So we make an OSX desktop app in LiveCode that has several document 
types. We add these to the info.plist file in the App bundle so they are 
defined, with doc icons, extensions, types, etc.

If a user has APPv1 installed that has a plist entry for the file 
extension .myext and then installs APPv2 that also has a plist entry for 
file extension .myext. how does OSX tell what APP to open when a user 
double clicks on document.myext?

I googled and found information on setting default app for document 
types, but not how OSX handles this by default?

In window, it is the App's responsibility to check the Registry for its 
document types and, it it wants to, ask the user if they want those 
document associated with it. Or it is done by the app's installer on Windows

I just can't find how OSX does it.

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