We have a couple systems that have the 2010 office suite with either Visio 2013 or Project 2013 installed as well. This appear to cause an issue with the Primary Interop Assemblies (PIA). When other applictions (Internet explorer or hyper links) try to open the office suite applications (Word or Excel) on these systems with the both the Office 2010 suite and either of these 2013 applications the file just doesn't open. From what we found it looks like the 2013 installs updates the PIA registry keys. So when these applications are trying to call word or excel it's trying to open 2013 versions of word or excel, which do not exist on the system. We found that if we locate the added interop keys for the 2013 word/excel and delete them the 2010 interop functionality then works again. How ever I'm assuming this wouldn't be a supported fix/workaround.
Is there any other way to stop this interop issue from occuring with the multiple 2010/2013 verison installs?