Apologies in advance - I'm not a developer.
I'm having an issue with a third-party web-based application that uses .NET and Silverlight. I don't know if it's formally .NET v2 or .NET v3.5 that it uses but we're using Windows 7 SP1 with .NET v3.5.1 installed. We have a group of PCs where a control does not appear on a page in the app. From what I can tell, these are connected with DLLs which are stored in "C:\windows\Downloaded Program Files" and should be being copied to the per-profile shadow copy assembly cache. On working machines, this cache is created ("c:\users\%username%\AppData\Local\assembly\dl3") correctly and populated with the DLLs. On faulty PCs, the assembly folder is not being created.
I've discovered that the PCs where it doesn't work have .NET v4.5 installed. Those that do work have v4.0. If I remove v4.5, it then works. If I then add v4.0 it still works. If I then add v4.5 it breaks again.
Is the fault likely to be with .NET or with the app?
Thanks for any thoughts!