diff --git a/daemon/disk_usage.go b/daemon/disk_usage.go
index a28463eba95a9..7142ef07811bb 100644
--- a/daemon/disk_usage.go
+++ b/daemon/disk_usage.go
@@ -99,7 +99,6 @@ func (daemon *Daemon) SystemDiskUsage(ctx context.Context) (*types.DiskUsage, er
 	for platform := range daemon.stores {
 		layerRefs := daemon.getLayerRefs(platform)
 		allLayers := daemon.stores[platform].layerStore.Map()
-		var allLayersSize int64
 		for _, l := range allLayers {
 			select {
 			case <-ctx.Done():