A lot of users are feeling a little confused about install protocol with the new Pro Tools Instrument Expansion Pack. So in the absence of advice from AVID, here it is:

1. Make a back-up of the libraries for the Plug-ins you are about to install for example; Structure, Strike and Transfuser Libraries.
2. Remove the original installations of the plug-ins (not the content) you are installing, depending on your OS you will need to remove the plug-ins, the preferences etc.
3. Create a folder called old content and then drop all the old content for Strike, Stucture and Tranfuser in their. You may never need them but it's a safe option.
4. Then do a clean install of your new plug-ins and let the installer do a default install.

Following these steps should give you a trouble free install and operation.