diff --git a/src/bindings/csharp/openalpr-net/config-net.h b/src/bindings/csharp/openalpr-net/config-net.h
index e591b1a..b1c7331 100644
--- a/src/bindings/csharp/openalpr-net/config-net.h
+++ b/src/bindings/csharp/openalpr-net/config-net.h
@@ -121,6 +121,11 @@ namespace openalprnet
 			}
 			void set(String^ value)
 			{
+				if(String::IsNullOrWhiteSpace(value))
+				{
+					this->m_config->prewarp = "";
+					return;
+				}
 				this->m_config->prewarp = marshal_as<std::string>(value);
 			}
 		}
@@ -407,6 +412,11 @@ namespace openalprnet
 			}
 			void set(String^ value)
 			{
+				if (String::IsNullOrWhiteSpace(value))
+				{
+					this->m_config->prewarp = "";
+					return;
+				}
 				this->m_config->ocrLanguage = marshal_as<std::string>(value);
 			}
 		}