diff --git a/platform/util/src/com/intellij/openapi/diagnostic/DefaultLogger.java b/platform/util/src/com/intellij/openapi/diagnostic/DefaultLogger.java
index 16b1360a7cfa..0943a0775ae1 100644
--- a/platform/util/src/com/intellij/openapi/diagnostic/DefaultLogger.java
+++ b/platform/util/src/com/intellij/openapi/diagnostic/DefaultLogger.java
@@ -77,9 +77,9 @@ public class DefaultLogger extends Logger {
   @Override
   public void setLevel(Level level) { }
 
-  public static String attachmentsToString(Throwable t) {
+  public static String attachmentsToString(@Nullable Throwable t) {
     //noinspection ThrowableResultOfMethodCallIgnored
-    Throwable rootCause = ExceptionUtil.getRootCause(t);
+    Throwable rootCause = t == null ? null : ExceptionUtil.getRootCause(t);
     if (rootCause instanceof ExceptionWithAttachments) {
       return "\nAttachments:" + StringUtil.join(((ExceptionWithAttachments)rootCause).getAttachments(),
                                                 new Function<Attachment, String>() {
diff --git a/platform/util/src/com/intellij/util/ExceptionUtil.java b/platform/util/src/com/intellij/util/ExceptionUtil.java
index 0f4491b04f3f..1fc03c880992 100644
--- a/platform/util/src/com/intellij/util/ExceptionUtil.java
+++ b/platform/util/src/com/intellij/util/ExceptionUtil.java
@@ -27,7 +27,8 @@ import java.util.Arrays;
 public class ExceptionUtil {
   private ExceptionUtil() { }
 
-  public static Throwable getRootCause(Throwable e) {
+  @NotNull
+  public static Throwable getRootCause(@NotNull Throwable e) {
     while (true) {
       if (e.getCause() == null) return e;
       e = e.getCause();