Question: When I open ane existing project in the designer, I get an exception:

Possible Version mismatch. Type System.Collections.Comparer has 1 members, number of members deserialized is 0.

What's the cause of this and how can I fix this?

Solution: This is caused by the fact that the project is saved on a machine with .NET 1.1 SP1 installed and your system doesn't have .NET 1.1 SP1 installed. Installing .NET 1.1 SP1 on the system on which you receive the exception will solve this so you can open the project again in the LLBLGen Pro designer on that system.