diff --git a/src/seedsigner/controller.py b/src/seedsigner/controller.py
index 4976d6f74..8f68c2647 100644
--- a/src/seedsigner/controller.py
+++ b/src/seedsigner/controller.py
@@ -309,7 +309,12 @@ def handle_exception(self, e) -> Destination:
         # So we extract the Exception type and trim off any "foo.bar." namespacing:
         last_line = traceback.format_exc().splitlines()[-1]
         exception_type = last_line.split(":")[0].split(".")[-1]
-        exception_msg = last_line.split(":")[1]
+
+        # Extract the error message, if there is one
+        if ":" in last_line:
+            exception_msg = last_line.split(":")[1]
+        else:
+            exception_msg = ""
 
         # Scan for the last debugging line that includes a line number reference
         line_info = None
diff --git a/tests/test_controller.py b/tests/test_controller.py
index bd8b2c18e..2fce03876 100644
--- a/tests/test_controller.py
+++ b/tests/test_controller.py
@@ -43,6 +43,48 @@ def test_singleton_get_instance_preserves_state(reset_controller):
     assert controller.unverified_address == "123abc"
 
 
+def test_handle_exception(reset_controller):
+    """ Handle exceptions that get caught by the controller """
+
+    def process_exception_asserting_valid_error(exception_type, exception_msg=None):
+        """
+        Exceptions caught by the controller are forwarded to the
+        UnhandledExceptionView with view_args["error"] being a list
+        of three strings, ie: [exception_type, line_info, exception_msg]
+        """
+        try:
+            if exception_msg:
+                raise exception_type(exception_msg)
+            else:
+                raise exception_type()
+        except Exception as e:
+            error = controller.handle_exception(e).view_args["error"]
+
+        # assert that error structure is valid
+        assert len(error) == 3
+        assert error[0] in str(exception_type)
+        assert type(error[1]) == str
+        if exception_msg:
+            assert exception_msg in error[2]
+        else:
+            assert error[2] == ""
+
+    # Initialize the controller
+    controller = Controller.get_instance()
+
+    exception_tests = [
+        # exceptions with an exception_msg
+        (Exception, "foo"),
+        (KeyError, "key not found"),
+        # exceptions without an exception_msg
+        (Exception, ""),
+        (Exception, None),
+    ]
+        
+    for exception_type, exception_msg in exception_tests:
+        process_exception_asserting_valid_error(exception_type, exception_msg)
+
+
 def test_missing_settings_get_defaults(reset_controller):
     """ Should gracefully handle all missing fields from `settings.json` """