diff --git a/Lib/sysconfig.py b/Lib/sysconfig.py
index d38974c..8ec399c 100644
--- a/Lib/sysconfig.py
+++ b/Lib/sysconfig.py
@@ -680,13 +680,16 @@
                 # behaviour.
                 pass
             else:
-                m = re.search(
-                        r'<key>ProductUserVisibleVersion</key>\s*' +
-                        r'<string>(.*?)</string>', f.read())
-                f.close()
-                if m is not None:
-                    macrelease = '.'.join(m.group(1).split('.')[:2])
-                # else: fall back to the default behaviour
+                try:
+                    m = re.search(
+                            r'<key>ProductUserVisibleVersion</key>\s*' +
+                            r'<string>(.*?)</string>', f.read())
+                    f.close()
+                    if m is not None:
+                        macrelease = '.'.join(m.group(1).split('.')[:2])
+                    # else: fall back to the default behaviour
+                finally:
+                    f.close()
 
         if not macver:
             macver = macrelease