diff --git a/nix-channels.py b/nix-channels.py
index 5b82c6c..c4fe06a 100755
--- a/nix-channels.py
+++ b/nix-channels.py
@@ -459,8 +459,8 @@ def garbage_collect():
         logging.info(f'  - {deleted} paths now unreachable')
 
 if __name__ == '__main__':
+    garbage_collect()
     channels = clone_channels()
     update_channels(channels)
-    garbage_collect()
     if failure:
         sys.exit(1)