Native Access is going to install its programs and libraries to the locations you specify. After installation, you can move the sound libraries to another location by copying them there and deleting from the original location. When you run Native Access again, it will know the sound content isn't there anymore and will give you the option to "locate" the sounds. Select the new folder and it should re-authorize the sounds and know to use them at the new location.
Keep in mind that Native Access will install to multiple places. The applications themselves (Kontakt Guitar Rig, Absynth, etc) will install to c:\Program Files (as do most programs). You can also specify where you want the associated VST2 files, and also where you want your associated sound libraries.
My configuration is:
- c:\Program Files\Native Instruments <-- location of main application
- c:\ProgramData\Native Instruments <-- miscellaneous files, looks to be mainly installation logs
- c:\Users\yourname\AppData\Local\AppName <-- cache files
- c:\Users\yourname\AppData\Roaming\Native Instruments\Native Access <-- various files related to Native Access
- c:\Apps\VST\64-bit\Native Instruments and c:\Apps\VST\32-bit\Native Instruments <-- location of VST2 files
- z:\Sounds\Native Instruments <-- all my Native Instrument sound libraries
- z:\Sounds\Kontakt Libraries <-- location of my 3rd party Kontakt libraries
While I really like the NI libraries, the one thing I don't like is that you can't download the individual installers (well, there's a way, but it's tricky and takes a long time). You have to download from their website every time using Native Access. That means a lot of bandwidth used when I rebuild my computer every so often. I have found that if I keep a full backup of the libraries, Native Access will allow me to use the "Locate" feature to re-establish the link between the programs and the libraries, but it doesn't work for all of them and I still have to download a bunch when I re-install.
Hopefully that helps some.