64 bit vs. 32 bit plugins - is there a setting somewhere?

I’m trying to make some AU plugins, and on Mac OSX, Digital Performer and Reaper can’t seem to see them, no matter where I put them (Library/Audio/Plug-Ins/Components or the User version) - and I’m wondering if this is perhaps because they want only 64-bit plugins and I am making 32bit versions?

Try rebooting. There is a bug in macOS where AU don’t show up until you reboot. Unlikely your making 32 but AU. The default has been 64 but for a long time and Xcode can’t even compile 32 bit code anymore.

Thanks, but I’ve rebooted repeatedly. Still can’t get them to show up in those DAWs - but they show up in the JUCE AudioPluginHost. And I’ve tried every possible “rescan” trick listed for those DAWs in google…

First thing to do is check the binary, you can use the file command:

file /Library/Audio/Plug-Ins/Components/Plugin.component/Contents/MacOS/Plugin 
/Library/Audio/Plug-Ins/Components/Plugin.component/Contents/MacOS/Plugin: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit bundle x86_64] [i386]
/Library/Audio/Plug-Ins/Components/Plugin.component/Contents/MacOS/Plugin (for architecture x86_64):	Mach-O 64-bit bundle x86_64
/Library/Audio/Plug-Ins/Components/Plugin.component/Contents/MacOS/Plugin (for architecture i386):	Mach-O bundle i386

This is a binary with x86/x64 (Universal) as an example.
Once you’re sure the binary is the right arch (although REAPER has built-in bridges so it supports x32/x64).

Older AU hosts expects a rsrc file and might not work without it. but if you’re using latest REAPER that shouldn’t be the case.
Also especially in REAPER, there’s AU and AUi so that Instruments would show up in a different tab.