diff --git a/src/apps/mail/MailApp.cpp b/src/apps/mail/MailApp.cpp
index 71d836589a..875898117c 100644
--- a/src/apps/mail/MailApp.cpp
+++ b/src/apps/mail/MailApp.cpp
@@ -460,6 +460,7 @@ TMailApp::ReadyToRun()
 	fs_create_index(volume.Device(), "MAIL:draft", B_INT32_TYPE, 0);
 	fs_create_index(volume.Device(), INDEX_SIGNATURE, B_STRING_TYPE, 0);
 	fs_create_index(volume.Device(), INDEX_STATUS, B_STRING_TYPE, 0);
+	fs_create_index(volume.Device(), B_MAIL_ATTR_FLAGS, B_INT32_TYPE, 0);
 
 	// Load dictionaries
 	BPath indexDir;