diff --git a/mig-runner/entity.go b/mig-runner/entity.go
index fdcc3a50..e39943ba 100644
--- a/mig-runner/entity.go
+++ b/mig-runner/entity.go
@@ -21,6 +21,7 @@ type entity struct {
 	confPath string
 	modTime  time.Time
 
+	deadChan chan bool
 	abortRun chan bool
 	cfg      entityConfig
 }
@@ -32,6 +33,17 @@ type entityConfig struct {
 	}
 }
 
+func (e *entityConfig) validate() error {
+	if e.Configuration.Schedule == "" {
+		return fmt.Errorf("missing schedule")
+	}
+	_, err := cronexpr.Parse(e.Configuration.Schedule)
+	if err != nil {
+		return fmt.Errorf("cron expression: %v", err)
+	}
+	return nil
+}
+
 func (e *entity) launchAction() (err error) {
 	defer func() {
 		if e := recover(); e != nil {
@@ -80,11 +92,16 @@ func (e *entity) launchAction() (err error) {
 }
 
 func (e *entity) start() {
+	xr := func(s string, args ...interface{}) {
+		mlog(s, args...)
+		e.deadChan <- true
+	}
+
 	e.abortRun = make(chan bool, 1)
 	for {
 		cexpr, err := cronexpr.Parse(e.cfg.Configuration.Schedule)
 		if err != nil {
-			mlog("%v: %v", e.name, err)
+			xr("%v: %v", e.name, err)
 			return
 		}
 		nrun := cexpr.Next(time.Now())
@@ -99,10 +116,12 @@ func (e *entity) start() {
 		mlog("%v: running", e.name)
 		err = e.launchAction()
 		if err != nil {
-			mlog("%v: %v", e.name, err)
+			xr("%v: %v", e.name, err)
 			return
 		}
 	}
+	mlog("%v: job exiting", e.name)
+	e.deadChan <- true
 }
 
 func (e *entity) stop() {
@@ -119,5 +138,18 @@ func (e *entity) load() (err error) {
 	if err != nil {
 		panic(err)
 	}
+
+	// Make sure an action file exists and is valid before we
+	// schedule this.
+	actpath := path.Join(e.baseDir, "action.json")
+	_, err = mig.ActionFromFile(actpath)
+	if err != nil {
+		panic(err)
+	}
+
+	err = e.cfg.validate()
+	if err != nil {
+		panic(err)
+	}
 	return nil
 }
diff --git a/mig-runner/main.go b/mig-runner/main.go
index d1c013b8..18880115 100644
--- a/mig-runner/main.go
+++ b/mig-runner/main.go
@@ -69,6 +69,7 @@ func procDir(dirpath string) (err error) {
 		mlog("%v: %v", ename, err)
 		return nil
 	}
+	ent.deadChan = make(chan bool, 1)
 	ctx.Entities[ename] = ent
 	mlog("added entity %v", ename)
 	go ent.start()
@@ -76,7 +77,8 @@ func procDir(dirpath string) (err error) {
 	return nil
 }
 
-// Remove entities that are no longer present in the runner directory
+// Remove entities that are no longer present in the runner directory, or are
+// stale
 func procReap(ents []string) error {
 	for k := range ctx.Entities {
 		found := false
@@ -91,6 +93,20 @@ func procReap(ents []string) error {
 			mlog("removed entity %v", k)
 		}
 	}
+	// Also remove stale entities that are still present in the runner
+	// directory but have encountered an error.
+	for k := range ctx.Entities {
+		dead := false
+		select {
+		case <-ctx.Entities[k].deadChan:
+			dead = true
+		default:
+		}
+		if dead {
+			delete(ctx.Entities, k)
+			mlog("removed stale entity %v", k)
+		}
+	}
 	return nil
 }