diff --git a/lib/bb/cooker.py b/lib/bb/cooker.py
index 48c3002ce3..815610ff82 100644
--- a/lib/bb/cooker.py
+++ b/lib/bb/cooker.py
@@ -1467,6 +1467,7 @@ class BBCooker:
         buildname = self.databuilder.mcdata[mc].getVar("BUILDNAME")
         if fireevents:
             bb.event.fire(bb.event.BuildStarted(buildname, [item]), self.databuilder.mcdata[mc])
+            bb.event.enable_heartbeat()
 
         # Execute the runqueue
         runlist = [[mc, item, task, fn]]
@@ -1500,6 +1501,7 @@ class BBCooker:
             if not retval:
                 if fireevents:
                     bb.event.fire(bb.event.BuildCompleted(len(rq.rqdata.runtaskentries), buildname, item, failures, interrupted), self.databuilder.mcdata[mc])
+                    bb.event.disable_heartbeat()
                 self.command.finishAsyncCommand(msg)
                 # We trashed self.recipecaches above
                 self.parsecache_valid = False
@@ -1545,6 +1547,7 @@ class BBCooker:
                     for mc in self.multiconfigs:
                         bb.event.fire(bb.event.BuildCompleted(len(rq.rqdata.runtaskentries), buildname, targets, failures, interrupted), self.databuilder.mcdata[mc])
                 finally:
+                    bb.event.disable_heartbeat()
                     self.command.finishAsyncCommand(msg)
                 return False
             if retval is True:
@@ -1578,6 +1581,7 @@ class BBCooker:
 
         for mc in self.multiconfigs:
             bb.event.fire(bb.event.BuildStarted(buildname, ntargets), self.databuilder.mcdata[mc])
+        bb.event.enable_heartbeat()
 
         rq = bb.runqueue.RunQueue(self, self.data, self.recipecaches, taskdata, runlist)
         if 'universe' in targets:
diff --git a/lib/bb/event.py b/lib/bb/event.py
index 97668601a1..21e9a1b025 100644
--- a/lib/bb/event.py
+++ b/lib/bb/event.py
@@ -69,6 +69,7 @@ _eventfilter = None
 _uiready = False
 _thread_lock = threading.Lock()
 _thread_lock_enabled = False
+_heartbeat_enabled = False
 
 if hasattr(__builtins__, '__setitem__'):
     builtins = __builtins__
@@ -83,6 +84,14 @@ def disable_threadlock():
     global _thread_lock_enabled
     _thread_lock_enabled = False
 
+def enable_heartbeat():
+    global _heartbeat_enabled
+    _heartbeat_enabled = True
+
+def disable_heartbeat():
+    global _heartbeat_enabled
+    _heartbeat_enabled = False
+
 def execute_handler(name, handler, event, d):
     event.data = d
     addedd = False
diff --git a/lib/bb/server/process.py b/lib/bb/server/process.py
index 586d46af88..91eb6e0ad9 100644
--- a/lib/bb/server/process.py
+++ b/lib/bb/server/process.py
@@ -382,7 +382,7 @@ class ProcessServer():
 
         # Create new heartbeat event?
         now = time.time()
-        if now >= self.next_heartbeat:
+        if bb.event._heartbeat_enabled and now >= self.next_heartbeat:
             # We might have missed heartbeats. Just trigger once in
             # that case and continue after the usual delay.
             self.next_heartbeat += self.heartbeat_seconds
@@ -396,7 +396,7 @@ class ProcessServer():
                     if not isinstance(exc, bb.BBHandledException):
                         logger.exception('Running heartbeat function')
                     self.quit = True
-        if nextsleep and now + nextsleep > self.next_heartbeat:
+        if nextsleep and bb.event._heartbeat_enabled and now + nextsleep > self.next_heartbeat:
             # Shorten timeout so that we we wake up in time for
             # the heartbeat.
             nextsleep = self.next_heartbeat - now