Our users are using a third-party system and every so often - a user might go all day without this happening, other days they may see it two or three times in seven hours - a red x will appear on screen rather than a button, field, or control.

This is a .net system.

Looking online I can see that this is a .net error. Problem is, our devs didn't write it, and the vendor wants proof that the problem resides with their system, not our PCs.

What can we do to gather information on such an issue that would allow us to make our case to the vendor and get them to create a fix? I'm thinking of data to gather - anything from OS, memory. .net version installed etc.

But I'd also like to know about error logging - if it's possible to log errors that occur in third-party systems.