diff --git a/build/org.eclipse.cdt.make.core/src/org/eclipse/cdt/make/core/MakeBuilder.java b/build/org.eclipse.cdt.make.core/src/org/eclipse/cdt/make/core/MakeBuilder.java
index 50a9e61e5e8..d70ab78ec1b 100644
--- a/build/org.eclipse.cdt.make.core/src/org/eclipse/cdt/make/core/MakeBuilder.java
+++ b/build/org.eclipse.cdt.make.core/src/org/eclipse/cdt/make/core/MakeBuilder.java
@@ -246,7 +246,9 @@ public class MakeBuilder extends ACBuilder {
 		if (info.appendEnvironment()) {
 			@SuppressWarnings({"unchecked", "rawtypes"})
 			Map<String, String> env = (Map)launcher.getEnvironment();
-			envMap.putAll(env);
+			if (env != null) {
+				envMap.putAll(env);
+			}
 		}
 		envMap.putAll(info.getExpandedEnvironment());
 		return envMap;