diff --git a/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/SdkConfigurationUtil.java b/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/SdkConfigurationUtil.java
index 3cc157a9291d..91bca1ccdaa4 100644
--- a/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/SdkConfigurationUtil.java
+++ b/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/SdkConfigurationUtil.java
@@ -168,7 +168,7 @@ public class SdkConfigurationUtil {
     return sdk;
   }
 
-  public static void setDirectoryProjectSdk(@NotNull final Project project, final Sdk sdk) {
+  public static void setDirectoryProjectSdk(@NotNull final Project project, @Nullable final Sdk sdk) {
     ApplicationManager.getApplication().runWriteAction(new Runnable() {
       public void run() {
         ProjectRootManager.getInstance(project).setProjectSdk(sdk);