diff --git a/config/pysource.win.bat b/config/pysource.win.bat
index 996823654fc51056836ec4a784885c652a6b585b..302ec1746d2250de25ff5df67c0b12df17f9d5f1 100644
--- a/config/pysource.win.bat
+++ b/config/pysource.win.bat
@@ -21,8 +21,8 @@ set python=python-3.7.9
 endlocal & (
   set "PATH=%TELEMACDEPS%\%python%;%TELEMACDEPS%\%python%\Scripts;%PATH%"
   set "PYTHONPATH=%TELEMACDEPS%\%python%\Lib\site-packages"
-  reg delete HKCU\SOFTWARE\Classes\.py\OpenWithProgids /f 1>null
-  reg add HKCU\SOFTWARE\Classes\.py\shell\open\command /ve /f /d "%TELEMACDEPS%\%python%\python.exe \"%%1\" %%*" 1>null
+  reg delete HKCU\SOFTWARE\Classes\.py\OpenWithProgids /f >nul 2>&1
+  reg add HKCU\SOFTWARE\Classes\.py\shell\open\command /ve /f /d "%TELEMACDEPS%\%python%\python.exe \"%%1\" %%*" 1>nul
 )
 
 rem Add Mingw to PATH is it is found
diff --git a/config/pysource.win.debug.bat b/config/pysource.win.debug.bat
index 7461cdf15a91f1dcac576aa40a905b713a8c4629..eccda77f3a4fe837203e45e38d5cb5d53ee4bf97 100644
--- a/config/pysource.win.debug.bat
+++ b/config/pysource.win.debug.bat
@@ -21,8 +21,8 @@ set python=python-3.7.9
 endlocal & (
   set "PATH=%TELEMACDEPS%\%python%;%TELEMACDEPS%\%python%\Scripts;%PATH%"
   set "PYTHONPATH=%TELEMACDEPS%\%python%\Lib\site-packages"
-  reg delete HKCU\SOFTWARE\Classes\.py\OpenWithProgids /f 1>null
-  reg add HKCU\SOFTWARE\Classes\.py\shell\open\command /ve /f /d "%TELEMACDEPS%\%python%\python.exe \"%%1\" %%*" 1>null
+  reg delete HKCU\SOFTWARE\Classes\.py\OpenWithProgids /f >nul 2>&1
+  reg add HKCU\SOFTWARE\Classes\.py\shell\open\command /ve /f /d "%TELEMACDEPS%\%python%\python.exe \"%%1\" %%*" 1>nul
 )
 
 rem Add Mingw to PATH is it is found