Problem solved, it was a directory setup problem with my Windows installation.
I was looking at someone else's project and kept seeing this error every time I loaded the project. I didn't realize that PSoC Desiger projects look for a file called PSoCConfig.xml by default. If a file by that name isn't present in your project folder, you'll see "The specified part is not loaded in the device library" upon trying to open a project.
In my case I didn't realize that this xml was given a bunch of aliases in my project folder. I was expected to rename the xml file I wanted to use, to get the associated project to load properly.