If you see an error like this “The following SData diagnosis occurred: Description=Operation failed. Message=Could not load type ‘Sage.Entity.Interfaces.ICollection`1’ from assembly ‘Sage.Entity.Interfaces’. HTTP status: Internal Server Error (500).” in the web client when opening an entity the issue could be a corrupted group.
We recently had a system where the Admin could not open the Users area under administration and the 500 error message was returned. The issue was the Allusers group was corrupt and the admin was set to use the Allusers group in the options.
Here are the steps to resolve:
1. Select options|groups|users and change the default group to another group like network users
2. Next click on users in the administration module
3.Find and hide the existing Allusers group
4.Finally build a new Allusers group and make it visible.
The same technique can be used for Account, Contact, Opportunity, Ticket, Defects, and any other entity that has a default group.