diff --git a/xpra/server/server_util.py b/xpra/server/server_util.py
index 2e83712bb8..2dd0bf73d2 100644
--- a/xpra/server/server_util.py
+++ b/xpra/server/server_util.py
@@ -166,6 +166,10 @@ def xpra_env_shell_script(socket_dir, env : Dict[str,str]) -> str:
     return "\n".join(script)
 
 def xpra_runner_shell_script(xpra_file:str, starting_dir:str) -> str:
+    # Nixpkgs contortion:
+    # xpra_file points to a shell wrapper, not to the python script.
+    dirname, basename = os.path.split(xpra_file)
+    xpra_file = os.path.join(dirname, "."+basename+"-wrapped")
     # We ignore failures in cd'ing, b/c it's entirely possible that we were
     # started from some temporary directory and all paths are absolute.
     qdir = sh_quotemeta(starting_dir)