--- imap/statuscache_db.c.orig	2012-12-01 20:57:54.000000000 +0100
+++ imap/statuscache_db.c	2013-10-18 17:09:42.110915989 +0200
@@ -152,7 +152,7 @@
     len = strlcpy(key, mailboxname, sizeof(key));
     key[len++] = '%';
     key[len++] = '%';
-    len += strlcpy(key + len, userid, sizeof(key) - len);
+    if (userid) len += strlcpy(key + len, userid, sizeof(key) - len);
 
     *keylen = len;