Script component source won't load when click "Edit Script..."

I'm working on an SSIS package in Visual Studio 2013. For any script component throughout the package, if I double-click on it and then click the "Edit Script..." button, Visual Studio 2012 opens but no editor window loads. It's just an empty window like you closed all documents. The Solution Explorer shows items, but notably "ScriptComponent" is an empty folder:

If I try to open any of the files (BufferWrapper.cs, ComponentWrapper.cs, main.cs) in the Solution Explorer, I get a popup error box saying:

Anyone have any clue what's going on here? FWIW, I have tried closing all instances of Visual Studio and reopening my solution with the SSIS package. The same behavior persists.

I stumbled across this blog post, which while the author didn't have the exact same problem as me, our issues seemed similar enough that his fix might work for me to. I downloaded the SSDT-BI 2012 package and installed it, and lo and behold, things work fine again. I'll just not even consider that somehow things worked fine for a year or more without downloading and installing SSDT-BI 2012, so I might be able to retain some portion of my sanity.

StackExchange Database Administrators Q#115108, answer score: 4