diff --git a/python_src/lasp/lasp_measurement.py b/python_src/lasp/lasp_measurement.py
index 09a2151..47b0093 100644
--- a/python_src/lasp/lasp_measurement.py
+++ b/python_src/lasp/lasp_measurement.py
@@ -986,7 +986,13 @@ 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:
-            uuid = f.attrs['UUID']
+            try:
+                uuid = f.attrs['UUID']
+            except AttributeError:
+                # 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())
 
         if uuid in Measurement.uuid_s.keys():
             return Measurement.uuid_s[uuid]