diff --git a/src/com/fsck/k9/mail/internet/MimeHeader.java b/src/com/fsck/k9/mail/internet/MimeHeader.java
index d45ba6878..49803b9b9 100644
--- a/src/com/fsck/k9/mail/internet/MimeHeader.java
+++ b/src/com/fsck/k9/mail/internet/MimeHeader.java
@@ -152,7 +152,7 @@ public class MimeHeader
         return false;
     }
 
-    class Field
+    static class Field
     {
         String name;