diff --git a/collectors/collectorManager.go b/collectors/collectorManager.go
index 52e91e7..f91db20 100644
--- a/collectors/collectorManager.go
+++ b/collectors/collectorManager.go
@@ -115,6 +115,7 @@ func (cm *collectorManager) Start() {
 			for _, c := range cm.collectors {
 				c.Close()
 			}
+			close(cm.done)
 			cclog.ComponentDebug("CollectorManager", "DONE")
 		}
 
@@ -154,6 +155,8 @@ func (cm *collectorManager) AddOutput(output chan lp.CCMetric) {
 func (cm *collectorManager) Close() {
 	cclog.ComponentDebug("CollectorManager", "CLOSE")
 	cm.done <- true
+	// wait for close of channel cm.done
+	<-cm.done
 }
 
 // New creates a new initialized metric collector manager
diff --git a/collectors/gpfsMetric.go b/collectors/gpfsMetric.go
index bc1852b..53db1c2 100644
--- a/collectors/gpfsMetric.go
+++ b/collectors/gpfsMetric.go
@@ -130,14 +130,21 @@ func (m *GpfsCollector) Read(interval time.Duration, output chan lp.CCMetric) {
 				continue
 			}
 
-			timestampInt, err := strconv.ParseInt(key_value["_t_"]+key_value["_tu_"], 10, 64)
-			timestamp := time.UnixMicro(timestampInt)
+			sec, err := strconv.ParseInt(key_value["_t_"], 10, 64)
 			if err != nil {
 				fmt.Fprintf(os.Stderr,
-					"GpfsCollector.Read(): Failed to convert time stamp '%s': %s\n",
-					key_value["_t_"]+key_value["_tu_"], err.Error())
+					"GpfsCollector.Read(): Failed to convert seconds to int '%s': %v\n",
+					key_value["_t_"], err)
 				continue
 			}
+			msec, err := strconv.ParseInt(key_value["_tu_"], 10, 64)
+			if err != nil {
+				fmt.Fprintf(os.Stderr,
+					"GpfsCollector.Read(): Failed to convert micro seconds to int '%s': %v\n",
+					key_value["_tu_"], err)
+				continue
+			}
+			timestamp := time.Unix(sec, msec*1000)
 
 			// bytes read
 			bytesRead, err := strconv.ParseInt(key_value["_br_"], 10, 64)
diff --git a/go.mod b/go.mod
index da4f3ea..0789f7e 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/ClusterCockpit/cc-metric-collector
 
-go 1.17
+go 1.16
 
 require (
 	github.com/NVIDIA/go-nvml v0.11.1-0
@@ -12,14 +12,7 @@ require (
 )
 
 require (
-	github.com/deepmap/oapi-codegen v1.8.2 // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/nats-io/nats-server/v2 v2.7.0 // indirect
-	github.com/nats-io/nkeys v0.3.0 // indirect
-	github.com/nats-io/nuid v1.0.1 // indirect
-	github.com/pkg/errors v0.9.1 // indirect
-	golang.org/x/crypto v0.0.0-20220112180741-5e0467b6c7ce // indirect
-	golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2 // indirect
 	google.golang.org/protobuf v1.27.1 // indirect
-	gopkg.in/yaml.v2 v2.3.0 // indirect
 )
diff --git a/internal/metricRouter/metricRouter.go b/internal/metricRouter/metricRouter.go
index e75e77d..96a2f05 100644
--- a/internal/metricRouter/metricRouter.go
+++ b/internal/metricRouter/metricRouter.go
@@ -101,6 +101,7 @@ func (r *metricRouter) StartTimer() {
 		for {
 			select {
 			case <-r.timerdone:
+				close(r.timerdone)
 				cclog.ComponentDebug("MetricRouter", "TIMER DONE")
 				return
 			case t := <-m:
@@ -195,6 +196,7 @@ func (r *metricRouter) Start() {
 
 	// Router manager is done
 	done := func() {
+		close(r.done)
 		cclog.ComponentDebug("MetricRouter", "DONE")
 	}
 
@@ -257,9 +259,13 @@ func (r *metricRouter) AddOutput(output chan lp.CCMetric) {
 func (r *metricRouter) Close() {
 	cclog.ComponentDebug("MetricRouter", "CLOSE")
 	r.done <- true
+	// wait for close of channel r.done
+	<-r.done
 	if r.config.IntervalStamp {
 		cclog.ComponentDebug("MetricRouter", "TIMER CLOSE")
 		r.timerdone <- true
+		// wait for close of channel r.timerdone
+		<-r.timerdone
 	}
 }
 
diff --git a/internal/multiChanTicker/multiChanTicker.go b/internal/multiChanTicker/multiChanTicker.go
index a9394ab..e0eca43 100644
--- a/internal/multiChanTicker/multiChanTicker.go
+++ b/internal/multiChanTicker/multiChanTicker.go
@@ -23,6 +23,7 @@ func (t *multiChanTicker) Init(duration time.Duration) {
 	t.done = make(chan bool)
 	go func() {
 		done := func() {
+			close(t.done)
 			cclog.ComponentDebug("MultiChanTicker", "DONE")
 		}
 		for {
@@ -52,6 +53,8 @@ func (t *multiChanTicker) AddChannel(channel chan time.Time) {
 func (t *multiChanTicker) Close() {
 	cclog.ComponentDebug("MultiChanTicker", "CLOSE")
 	t.done <- true
+	// wait for close of channel t.done
+	<-t.done
 }
 
 func NewTicker(duration time.Duration) MultiChanTicker {
diff --git a/sinks/sinkManager.go b/sinks/sinkManager.go
index b4b3dc5..8d2872a 100644
--- a/sinks/sinkManager.go
+++ b/sinks/sinkManager.go
@@ -81,6 +81,7 @@ func (sm *sinkManager) Start() {
 				s.Close()
 			}
 
+			close(sm.done)
 			cclog.ComponentDebug("SinkManager", "DONE")
 		}
 
@@ -149,6 +150,8 @@ func (sm *sinkManager) AddOutput(rawConfig json.RawMessage) error {
 func (sm *sinkManager) Close() {
 	cclog.ComponentDebug("SinkManager", "CLOSE")
 	sm.done <- true
+	// wait for close of channel sm.done
+	<-sm.done
 }
 
 // New creates a new initialized sink manager