diff --git a/usr/lib/python3.6/lxcmgr/pkgmgr.py b/usr/lib/python3.6/lxcmgr/pkgmgr.py
index 47d59ba..bc17b91 100644
--- a/usr/lib/python3.6/lxcmgr/pkgmgr.py
+++ b/usr/lib/python3.6/lxcmgr/pkgmgr.py
@@ -251,7 +251,8 @@ class PkgMgr:
                 image = self.installed_packages['apps'][app]['containers'][container]['image']
                 for layer in self.installed_packages['images'][image]['layers']:
                     if layer in layers:
-                        del layers[layer]
+                        # Layer is still used, remove from set of layers to be purged
+                        layers.remove(layer)
         for layer in layers:
             self.purge_layer(layer)