500px Aperture Uploader Cannot Run in 32 bit Mode

If you get the following alert when trying to run the 500px Aperture Uploader, it's because Aperture is running in 32-bit mode.

The 500px Aperture Uploader requires Aperture to be running in 64-bit mode to work. To do this, first quit Aperture and find the application on your computer - it's typically in your computer's Applications folder.

Once you've found it, right-click Aperture and choose "Get Info...", or click it once and choose "Get Info..." from the Finder's "File" menu.

When the Info window appears, make sure the "Open in 32-bit mode" is unticked.

Finally, close the Info window and re-launch Aperture. The 500px Aperture Uploader will then function normally.