diff --git a/lib/lyx2lyx/LyX.py b/lib/lyx2lyx/LyX.py
index 18088a4dea..39a77e3827 100644
--- a/lib/lyx2lyx/LyX.py
+++ b/lib/lyx2lyx/LyX.py
@@ -345,7 +345,7 @@ class LyX_base:
             if check_token(decoded, '\\end_preamble'):
                 continue
 
-            line = line.strip()
+            line = line.rstrip()
             if not line:
                 continue