Recent Microsoft .NET Updates Incompatible with ScaleOut versions prior to 5.5


Staff member
Recent updates to the .NET Framework (starting with .NET 4.7.1) are incompatible with older versions of ScaleOut's .NET client libraries (versions prior to 5.5, released 2016-Dec-29). This incompatibility stems from recent changes made to .NET's JIT compilation engine.

Customer Impact
Starting in mid-2018, several customers running older versions of the ScaleOut Product Suite (pre-5.5) have reported problems with their applications after applying updates and/or security rollups from Microsoft. Initial symptoms typically involve ScaleOut read operations not finding the object associated with a key when it is known to exist in the ScaleOut data grid.

If you believe you are affected then you have two ways to address the issue:
  • (Preferred) Upgrade to the latest version of ScaleOut StateServer, available for download here.
  • Configure your systems to use .NET’s legacy JIT. You can make this change through your application's config file, by modifying your registry, or by setting an environment variable--more details are here. (If you go this route, a number of customers have had the most success using the registry key.)