diff --git a/install/MarcMentat/apply_DAMASK_modifications.py b/install/MarcMentat/apply_DAMASK_modifications.py
index 3ed167039..60184bafa 100755
--- a/install/MarcMentat/apply_DAMASK_modifications.py
+++ b/install/MarcMentat/apply_DAMASK_modifications.py
@@ -14,9 +14,8 @@ def copy_and_patch(patch,orig,marc_root,editor):
     except shutil.SameFileError:
         pass
     damask.util.run(f'patch {orig.parent/patch.stem} {patch} -b')
-    with open(orig.parent/patch.stem) as f_in:
+    with open(orig.parent/patch.stem) as f_in, open(orig.parent/patch.stem,'w') as f_out:
         content = f_in.read()
-    with open(orig.parent/patch.stem,'w') as f_out:
         f_out.write(content.replace('%INSTALLDIR%',f'{marc_root}').replace('%EDITOR%',editor))