I've come across this issue randomly a couple of times over the past few months and have just had some time tonight to troubleshoot the problem and post it up here.
The issue relates to the Visio add-in for System Center 2012 - Operations Manager (SCOM/OpsMgr 2012) and the fact that in some cases, it simply doesn't load into Visio as it should do.
Typically, in my lab or test environments, if I am configuring theVisio and SharePoint integration of SCOM 2012 using the 'Visio 2010 and SharePoint 2010 Extensions for System Center 2012', I would download the file, unzip it and then run the Visio add-in installer on the computer that was running Visio 2010 Professional or Premium edition.
Generally, this would install without any issues and as soon as I open up Visio, the integration tab for Operations Manager is available. In some instances however, after the Visio add-in installer completed successfully, when I opened up Visio, the add-in wouldn't launch at all.
To troubleshoot, I opened up the Add-Ins tab from the File > Options menu inside Visio as below
When I clicked on the Go button to manage the COM Add-Ins, I was presented with a screen similar to the one below. I could also see from that screen that the Load Behavior was configured to 'Load at Startup', which means that I shouldn't have to do anything for the Add-In to start.
If I clicked on the check box for the add-in and then chose the OK button, the window would simply close with no warning and when I went back into it, I could see that the Load Behavior message had changed to the following:
Load Behavior: Not loaded. A runtime error occurred during the loading of the COM Add-in.
The solution to this problem in the end was actually quite simple. I found that the error tended to only occur when I was installing the add-in onto a server that had Visio installed on it as opposed to a client pc or laptop. In my lab/demo environments, I would normally just deploy Visio onto one of my SCOM management servers and enable the 'Desktop Experience' feature to allow for uploading graphics to SharePoint.
If I tried running the Visio add-in installer from a client pc or laptop, it always worked for me without issue so I went about comparing software prerequisites for the Visio add-in between my laptop and my servers. What I found was that on the server, I was missing the Visual Studio 2010 Tools for Office Runtime (VSTOR) and this was listed as a requirement in the Visio and SharePoint extensions documentation.
If you have encountered this problem, then all you need to do is to go to the following URL and download the VSTOR package for your architecture (x86 or x64):
Once you have downloaded the tools, run the installer as an administrator and follow these screens to configure
When the tools have finished installing, open up Visio 2010 again and you should now be presented with an option to Install or Don't Install the Visio Add-In for System Center 2012 - Operations Manager. Click Install to continue
After you click Install, you will then be able to see the Operations Manager add-in tab from within you Visio window allowing you to configure integration to your SCOM 2012 management server.
Hopefully someone finds this quick solution helpful!