How can I find out which Mac apps are 32-bit?
In the Finder hit cmdF to get a search window.


Choose Search: This Mac
Hit the first search criterion and choose "Other..." and here "Executable Architectures" "Is" "i386"
Hit the + button and add a second criterion "Executable Architectures" "Is not" "x86_64"




and you will get a list of all i386 only (i.e. 32-bit) apps.



In Terminal this is done with:

mdfind "(kMDItemExecutableArchitectures == 'i386') &amp;&amp; (kMDItemExecutableArchitectures != 'x86_64')"