diff --git a/platform/util/src/com/intellij/util/xmlb/PropertyAccessor.java b/platform/util/src/com/intellij/util/xmlb/PropertyAccessor.java
index 60a7152a01ff..669249084a47 100644
--- a/platform/util/src/com/intellij/util/xmlb/PropertyAccessor.java
+++ b/platform/util/src/com/intellij/util/xmlb/PropertyAccessor.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2017 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,6 +25,8 @@ import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Type;
 
+import static com.intellij.util.xmlb.Binding.LOG;
+
 class PropertyAccessor implements MutableAccessor {
   private final String myName;
   private final Class<?> myType;
@@ -72,7 +74,26 @@ class PropertyAccessor implements MutableAccessor {
       throw new XmlSerializationException(e);
     }
     catch (InvocationTargetException e) {
-      throw new XmlSerializationException(e);
+      Throwable cause = e.getCause();
+      // see KotlinXmlSerializerTest.nullInMap
+      if (cause instanceof IllegalArgumentException && myGenericType instanceof Class && ((Class)myGenericType).isEnum() && cause.getMessage().contains("Parameter specified as non-null is null:")) {
+        Object[] constants = ((Class)myGenericType).getEnumConstants();
+        if (constants.length > 0) {
+          try {
+            LOG.warn("Cannot set enum value, will be set to first enum value", e);
+            myWriteMethod.invoke(host, constants[0]);
+            return;
+          }
+          catch (IllegalAccessException e1) {
+            throw new XmlSerializationException(e);
+          }
+          catch (InvocationTargetException e1) {
+            throw new XmlSerializationException(cause);
+          }
+        }
+      }
+
+      throw new XmlSerializationException(cause);
     }
   }
 
diff --git a/platform/util/testSrc/com/intellij/util/xmlb/KotlinXmlSerializerTest.kt b/platform/util/testSrc/com/intellij/util/xmlb/KotlinXmlSerializerTest.kt
new file mode 100644
index 000000000000..ef624e25c4a9
--- /dev/null
+++ b/platform/util/testSrc/com/intellij/util/xmlb/KotlinXmlSerializerTest.kt
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2000-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.util.xmlb
+
+import com.intellij.util.loadElement
+import com.intellij.util.xmlb.annotations.MapAnnotation
+import com.intellij.util.xmlb.annotations.Tag
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.Test
+import java.util.*
+
+class KotlinXmlSerializerTest {
+  @Test fun internalVar() {
+    @Tag("bean")
+    class Foo {
+      internal var PLACES_MAP = ""
+    }
+
+    val data = Foo()
+    data.PLACES_MAP = "new"
+    doSerializerTest("""
+    <bean>
+      <option name="PLACES_MAP" value="new" />
+    </bean>""", data)
+  }
+
+  @Test fun nullInMap() {
+    @Tag("bean")
+    class Foo {
+      @MapAnnotation(surroundWithTag = false, surroundKeyWithTag = false, surroundValueWithTag = false)
+      var PLACES_MAP: TreeMap<String, PlaceSettings> = TreeMap()
+    }
+
+    val data = Foo()
+    data.PLACES_MAP.put("", PlaceSettings())
+    doSerializerTest("""
+    <bean>
+      <option name="PLACES_MAP">
+        <entry key="">
+          <PlaceSettings>
+            <option name="IGNORE_POLICY" value="DEFAULT" />
+          </PlaceSettings>
+        </entry>
+      </option>
+    </bean>""", data)
+
+    assertThat(XmlSerializer.deserialize(loadElement("""<bean>
+      <option name="PLACES_MAP">
+        <entry key="">
+          <PlaceSettings>
+            <option name="IGNORE_POLICY" />
+          </PlaceSettings>
+        </entry>
+      </option>
+    </bean>"""), Foo::class.java)!!.PLACES_MAP.get("")!!.IGNORE_POLICY).isEqualTo(IgnorePolicy.DEFAULT)
+
+    assertThat(XmlSerializer.deserialize(loadElement("""<bean>
+      <option name="PLACES_MAP">
+        <entry key="">
+          <PlaceSettings>
+            <option name="SOME_UNKNOWN_VALUE" />
+          </PlaceSettings>
+        </entry>
+      </option>
+    </bean>"""), Foo::class.java)!!.PLACES_MAP.get("")!!.IGNORE_POLICY).isEqualTo(IgnorePolicy.DEFAULT)
+  }
+}
+
+private enum class IgnorePolicy constructor(val text: String) {
+  DEFAULT("Do not ignore"),
+  TRIM_WHITESPACES("Trim whitespaces"),
+  IGNORE_WHITESPACES("Ignore whitespaces"),
+  IGNORE_WHITESPACES_CHUNKS("Ignore whitespaces and empty lines"),
+  FORMATTING("Ignore formatting");
+}
+
+private data class PlaceSettings(var IGNORE_POLICY: IgnorePolicy = IgnorePolicy.DEFAULT)
diff --git a/platform/util/testSrc/com/intellij/util/xmlb/XmlSerializerTest.kt b/platform/util/testSrc/com/intellij/util/xmlb/XmlSerializerTest.kt
index 0f57ef7a16e9..9e1ca3e6f87e 100644
--- a/platform/util/testSrc/com/intellij/util/xmlb/XmlSerializerTest.kt
+++ b/platform/util/testSrc/com/intellij/util/xmlb/XmlSerializerTest.kt
@@ -61,20 +61,6 @@ internal class BeanWithProperty {
 }
 
 internal class XmlSerializerTest {
-  @Test fun internalVar() {
-    @Tag("bean")
-    class Foo {
-      internal var PLACES_MAP = ""
-    }
-
-    val data = Foo()
-    data.PLACES_MAP = "new"
-    doSerializerTest("""
-    <bean>
-      <option name="PLACES_MAP" value="new" />
-    </bean>""", data)
-  }
-
   @Test fun annotatedInternalVar() {
     @Tag("bean")
     class Foo {