diff --git a/python_src/lasp/lasp_measurement.py b/python_src/lasp/lasp_measurement.py
index 47b0093..381466d 100644
--- a/python_src/lasp/lasp_measurement.py
+++ b/python_src/lasp/lasp_measurement.py
@@ -987,15 +987,15 @@ class Measurement:
         # See if the base part of the filename is referring to a file that is already open
         with h5.File(fn, 'r') as f:
             try:
-                uuid = f.attrs['UUID']
-            except AttributeError:
+                theuuid = f.attrs['UUID']
+            except KeyError:
                 # No UUID stored in measurement. This is an old measurement that did not have UUID's
                 # We create a new UUID here such that the file is opened from the filesystem
                 # anyhow.
-                uuid = str(uuid.uuid1())
+                theuuid = str(uuid.uuid1())
 
-        if uuid in Measurement.uuid_s.keys():
-            return Measurement.uuid_s[uuid]
+        if theuuid in Measurement.uuid_s.keys():
+            return Measurement.uuid_s[theuuid]
         
         return Measurement(fn)