diff --git a/src/qemu/qemu_agent.c b/src/qemu/qemu_agent.c
index 3f6a9bf889..fc23c41edb 100644
--- a/src/qemu/qemu_agent.c
+++ b/src/qemu/qemu_agent.c
@@ -92,6 +92,7 @@ struct _qemuAgent {
     int watch;
 
     bool connectPending;
+    bool running;
 
     virDomainObjPtr vm;
 
@@ -772,6 +773,7 @@ qemuAgentOpen(virDomainObjPtr vm,
         goto cleanup;
     }
 
+    mon->running = true;
     VIR_DEBUG("New mon %p fd =%d watch=%d", mon, mon->fd, mon->watch);
 
     return mon;
@@ -788,6 +790,36 @@ qemuAgentOpen(virDomainObjPtr vm,
 }
 
 
+static void
+qemuAgentNotifyCloseLocked(qemuAgentPtr mon)
+{
+    if (mon) {
+        mon->running = false;
+
+        /* If there is somebody waiting for a message
+         * wake him up. No message will arrive anyway. */
+        if (mon->msg && !mon->msg->finished) {
+            mon->msg->finished = 1;
+            virCondSignal(&mon->notify);
+        }
+    }
+}
+
+
+void
+qemuAgentNotifyClose(qemuAgentPtr mon)
+{
+    if (!mon)
+        return;
+
+    VIR_DEBUG("mon=%p", mon);
+
+    virObjectLock(mon);
+    qemuAgentNotifyCloseLocked(mon);
+    virObjectUnlock(mon);
+}
+
+
 void qemuAgentClose(qemuAgentPtr mon)
 {
     if (!mon)
@@ -803,12 +835,7 @@ void qemuAgentClose(qemuAgentPtr mon)
         VIR_FORCE_CLOSE(mon->fd);
     }
 
-    /* If there is somebody waiting for a message
-     * wake him up. No message will arrive anyway. */
-    if (mon->msg && !mon->msg->finished) {
-        mon->msg->finished = 1;
-        virCondSignal(&mon->notify);
-    }
+    qemuAgentNotifyCloseLocked(mon);
     virObjectUnlock(mon);
 
     virObjectUnref(mon);
@@ -1087,6 +1114,12 @@ qemuAgentCommand(qemuAgentPtr mon,
 
     *reply = NULL;
 
+    if (!mon->running) {
+        virReportError(VIR_ERR_AGENT_UNRESPONSIVE, "%s",
+                       _("Guest agent disappeared while executing command"));
+        return -1;
+    }
+
     if (qemuAgentGuestSync(mon) < 0)
         return -1;
 
@@ -1112,8 +1145,12 @@ qemuAgentCommand(qemuAgentPtr mon,
             if (await_event && !needReply) {
                 VIR_DEBUG("Woken up by event %d", await_event);
             } else {
-                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                               _("Missing monitor reply object"));
+                if (mon->running)
+                    virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                                   _("Missing monitor reply object"));
+                else
+                    virReportError(VIR_ERR_AGENT_UNRESPONSIVE, "%s",
+                                   _("Guest agent disappeared while executing command"));
                 ret = -1;
             }
         } else {
diff --git a/src/qemu/qemu_agent.h b/src/qemu/qemu_agent.h
index 1cd5749403..988228bd23 100644
--- a/src/qemu/qemu_agent.h
+++ b/src/qemu/qemu_agent.h
@@ -49,6 +49,8 @@ qemuAgentPtr qemuAgentOpen(virDomainObjPtr vm,
 
 void qemuAgentClose(qemuAgentPtr mon);
 
+void qemuAgentNotifyClose(qemuAgentPtr mon);
+
 typedef enum {
     QEMU_AGENT_EVENT_NONE = 0,
     QEMU_AGENT_EVENT_SHUTDOWN,
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 537797ea3c..f40ccae179 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -4480,6 +4480,14 @@ processSerialChangedEvent(virQEMUDriverPtr driver,
     VIR_DEBUG("Changing serial port state %s in domain %p %s",
               devAlias, vm, vm->def->name);
 
+    if (newstate == VIR_DOMAIN_CHR_DEVICE_STATE_DISCONNECTED &&
+        virDomainObjIsActive(vm) && priv->agent) {
+        /* Close agent monitor early, so that other threads
+         * waiting for the agent to reply can finish and our
+         * job we acquire below can succeed. */
+       qemuAgentNotifyClose(priv->agent);
+    }
+
     if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
         goto cleanup;