diff --git a/src/main-export-known-hosts.py b/src/main-export-known-hosts.py
index 63288b9..6cda64c 100644
--- a/src/main-export-known-hosts.py
+++ b/src/main-export-known-hosts.py
@@ -48,8 +48,8 @@ def main():
 
 	try:
 		homedir = os.environ['HOME']
-	except KeyError:
-		raise KeyError('$HOME is not set')
+	except KeyError as err:
+		raise KeyError('$HOME is not set') from err
 
 	# The input file
 	# Default to ~/.ssh/known_hosts