Why does FxFactory warn me about multiple copies being installed?

FxFactory will sometimes warn you when it finds more than one copy of itself on the system, or if it determines that it is being loaded from an external drive. While these alerts may be annoying, they serve a very important purpose.

The visual effect plug-in SDK used by Final Cut Pro and Motion is called FxPlug, and it sits on top of a technology called PlugInKit.

Final Cut Pro and Motion rely on PlugInKit to locate and load third-party plug-ins and extensions. The same technology is also used to locate and load some internal components.

This technology may sometimes follow rules that don't make sense, causing problems when there are backup disks (or other bootable volumes) connected to your Mac that contain additional copies of apps and plug-ins.

For example, after you upgrade Final Cut Pro, Motion or FxFactory, an external backup drive will often contain an older version. Ignoring the upgrade, PlugInKit may wrongfully decide to try and load old components found on the external drive.

It would make more sense for PlugInKit to give precedence to the most recent components found on the system, or perhaps to components found on the same drive as the app you’re launching. But this is not guaranteed.

In order to have a predictable environment, FxFactory will therefore warn you and give you a chance to remove any duplicates from the system. Alternatively, you can unmount all backup drives before launching Final Cut Pro or Motion.