GroupWise 8 and Outlook 2013 on same workstation.

I know I'm asking about an old version of GroupWise here, but unfortunately, I'm stuck with it for the moment (not a big fan myself). Thought I'd take a shot here and see if anyone has an idea.

I have a few Windows 7 systems that are running GroupWise 8. These systems also need Microsoft Office (they're not using Outlook but need Word, Excel, etc). I can get both installed fine, but these newer systems are running the "Click to run" version of Office 2013, which to the best of my knowledge doesn't allow a "custom" install without Outlook.

Problem is that the GroupWise 8 client will work great - once. I can send/receive emails, dig through the address book, and pretty much do anything I want. However, after I close it, I get the following next time I try to open it:
"Groupwise is not properly installed. The Groupwise components could not be initialized. Please run GroupWise setup, or contact your system administrator."

I've found that I can go to Control Panel -> Mail, show profiles, delete the profile (Novell Groupwise is the only listing there), open GroupWise, and it works perfectly. Again, only until I close it, then it reverts back to the above. I get the error again next time I try to open it.

Things I've tried:
- Remove/reinstall GroupWise (no luck).
- Remove both GroupWise AND MS Office 2013 and reinstall them in different orders (no luck).
- Verified that GroupWise 8 is set for all its defaults in Default Programs (it is).
- Run Outlook once (without setting anything up) and let it create a profile, THEN open GroupWise. No luck.

This has something to do with the fact that GroupWise 8 and Outlook 2013 are on the same machine, because GroupWise 8 works fine if I completely remove Office 2013. Problem is...the users kinda need Office 2013. Anyone dealt with this before and have an idea of what to do? Currently, I just have users of the affected workstations running with GroupWise web access, but that's a Band-Aid fix at best. This is happening on about 5-6 different workstations (the rest are all running Office 2010 custom installs without Outlook).

I am trying to convince them to upgrade to GroupWise 2014 or switch to something else entirely, but right now I'm not having much luck there.