diff --git a/plugins/maven/src/main/java/org/jetbrains/idea/maven/project/MavenProject.java b/plugins/maven/src/main/java/org/jetbrains/idea/maven/project/MavenProject.java
index f6dbfa657089..767438724e2a 100644
--- a/plugins/maven/src/main/java/org/jetbrains/idea/maven/project/MavenProject.java
+++ b/plugins/maven/src/main/java/org/jetbrains/idea/maven/project/MavenProject.java
@@ -891,7 +891,7 @@ public class MavenProject {
     volatile List<MavenPlugin> myUnresolvedPluginsCache;
     volatile List<MavenArtifact> myUnresolvedExtensionsCache;
 
-    ConcurrentHashMap<Key, Object> myCache = new ConcurrentHashMap<Key, Object>();
+    transient ConcurrentHashMap<Key, Object> myCache = new ConcurrentHashMap<Key, Object>();
 
     @Override
     public State clone() {
@@ -940,5 +940,10 @@ public class MavenProject {
 
       return result;
     }
+
+    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
+      in.defaultReadObject();
+      myCache = new ConcurrentHashMap<Key, Object>();
+    }
   }
 }