Well folks, it’s time to clean house. Those 32-bit plug-ins are toast. If you try to launch one you’ll see the message below:
We’ve already heard some users are perturbed that they weren’t warned before installing the Aperture 3.3 update that their legacy plugins wouldn’t work.
Aperture went 64-bit two years ago with Snow Leopard, then with Lion it went full 64-bit, and apparently Mountain Lion will drop 32-bit support entirely.
NOTE: The plugin in the screenshot above is an outdated version of Viveza; Nik Software updated all of its plugins to 64-bit quite some time ago.
There are, however, other plugins out there that have not been updated.