diff --git a/webnotes/utils/__init__.py b/webnotes/utils/__init__.py
index 5d6b2ed6a7..e0a4ba71e9 100644
--- a/webnotes/utils/__init__.py
+++ b/webnotes/utils/__init__.py
@@ -910,5 +910,9 @@ def get_site_name(hostname):
 
 def get_disk_usage():
 	"""get disk usage of files folder"""
-	err, out = execute_in_shell("du -hsm {files_path}".format(files_path=get_files_path()))
-	return cint(out.split("\n")[-2].split("\t")[0])
\ No newline at end of file
+	import os
+	files_path = get_files_path()
+	if not os.path.exists(files_path):
+		return 0
+	err, out = execute_in_shell("du -hsm {files_path}".format(files_path=files_path))
+	return cint(out.split("\n")[-2].split("\t")[0])
diff --git a/wnf.py b/wnf.py
index f72758805d..1b24fd97f4 100755
--- a/wnf.py
+++ b/wnf.py
@@ -348,6 +348,7 @@ def backup(site=None, with_files=False, verbose=True, backup_path_db=None, backu
 		print "database backup taken -", odb.backup_path_db, "- on", now()
 		if with_files:
 			print "files backup taken -", odb.backup_path_files, "- on", now()
+	webnotes.destroy()
 	return odb
 
 @cmd