Here recently the speed at which the Kontakt Player 2 loads the sounds in Sibelius have slowed down tremendously. It takes 3 seconds for the default *Metronome* to load when I used to not even see it. The specs are as follows:

Virtual Drumline 2.5.2
Sibelius 6.1
RAM 4.0GB
Processor: Intel Core 2 Duo 1.30 GHz

Any ideas?

Does this happen after a restart of your computer? Is any security software scanning your hard drive when you try to load any sounds?

Also, does the same thing happen if you open the Kontakt Player 2 in Standalone mode and try to load some multis?

I disabled my anti-virus software and the speed picked tremendously, but the software doesn't scan files unless I tell it to.

My anti-virus software: Kaspersky Anti-Virus 11

Another thing you may notice is that the first time it tries to load sounds takes a bit longer than successive loads in the same session. I'm not sure exactly why this happens, but it seems to have been improved quite a bit with Kontakt Player 4. You might want to try using that over Kontakt Player 2. Kontakt Player 4 is available as a free download at the NI site here:
http://www.native-instruments.com/#/en/products/producer/kontakt-player/?page=781

One thing though...if you're going to try using Kontakt Player 4, I seem to recall it'll require you to update your Sibelius software to the latest version (currently 6.2) to properly recognize it as a Kontakt style plugin. This is important if you're using the VDL sound set in your Playback Devices.

Thanks for the tip Jim. I do know that loads are longer when you first start, but this was happening all the time. Even if I had something loaded and then changed the instrumentation.