Trying to have multiple (platform-dependent) versions of the equivalent DLL but receiving error on build. This seems to be thing with the "Define Constraints" field on Import Settings. But here's the test setup: Code (csharp): - Assets/ - SampleScriptUsingSampleDll.cs - Plugins/ - Sample (DEBUG)/ - Sample.dll (Define Constraints:) "DEBUG" - Sample (RELEASE)/ - Sample.dll (Define Constraints:) "!DEBUG" Work fine in the editor! Only the DEBUG variant is active. However, trying to build I receive the following errors: It's like the constraint is ignore in an early stage of the build. Is this a known problem and/or does anyone have any ideas of a workaround? Thank you for all yours times.