Index: channels/chan_dahdi.c
===================================================================
--- channels/chan_dahdi.c	(revision 167416)
+++ channels/chan_dahdi.c	(working copy)
@@ -8185,7 +8185,8 @@
 				if (!found && ((i == last) || ((i == iflist) && !last))) {
 					last = i;
 					if (last) {
-						if (!last->mwisendactive &&	 last->sig & __DAHDI_SIG_FXO) {
+						if (!last->mwisendactive && !last->owner && !ast_strlen_zero(last->mailbox) && 
+								(thispass - last->onhooktime > 3) && last->sig & __DAHDI_SIG_FXO) {
 							res = has_voicemail(last);
 							if (last->msgstate != res) {
 								/* Set driver resources for signalling VMWI */