diff --git a/picard/formats/apev2.py b/picard/formats/apev2.py
index 940f23c32..faa0bb5d0 100644
--- a/picard/formats/apev2.py
+++ b/picard/formats/apev2.py
@@ -275,7 +275,8 @@ class OptimFROGFile(APEv2File):
 
     def _info(self, metadata, file):
         super()._info(metadata, file)
-        if file.filename.lower().endswith(".ofs"):
+        # mutagen.File.filename can be either a bytes or str object
+        if string_(file.filename.lower()).endswith(".ofs"):
             metadata['~format'] = "OptimFROG DualStream Audio"
         else:
             metadata['~format'] = "OptimFROG Lossless Audio"
diff --git a/picard/plugin.py b/picard/plugin.py
index 31c0b93ad..ced6ee6d7 100644
--- a/picard/plugin.py
+++ b/picard/plugin.py
@@ -446,7 +446,7 @@ class PluginManager(QtCore.QObject):
                     try:
                         installed_plugin = self.load_plugin(zip_plugin or plugin_name, USER_PLUGIN_DIR)
                     except Exception as e:
-                        log.error('Unable to load plugin: %s.\nError occured: %s', name, e)
+                        log.error('Unable to load plugin: %s.\nError occured: %s', plugin_name, e)
                         installed_plugin = None
 
                     if installed_plugin is not None:
diff --git a/test/data/test.ofr b/test/data/test.ofr
new file mode 100644
index 000000000..3e0d3240f
Binary files /dev/null and b/test/data/test.ofr differ
diff --git a/test/data/test.ofs b/test/data/test.ofs
new file mode 100644
index 000000000..3e0d3240f
Binary files /dev/null and b/test/data/test.ofs differ
diff --git a/test/test_formats.py b/test/test_formats.py
index ea00d29a0..5470a71cb 100644
--- a/test/test_formats.py
+++ b/test/test_formats.py
@@ -534,6 +534,24 @@ class TAKTest(CommonTests.FormatsTest):
     supports_ratings = False
 
 
+class OptimFROGLosslessTest(CommonTests.FormatsTest):
+    testfile = 'test.ofr'
+    supports_ratings = False
+
+    def test_format(self):
+        metadata = load_metadata(self.filename)
+        self.assertEqual(metadata['~format'], 'OptimFROG Lossless Audio')
+
+
+class OptimFROGDUalStreamTest(CommonTests.FormatsTest):
+    testfile = 'test.ofs'
+    supports_ratings = False
+
+    def test_format(self):
+        metadata = load_metadata(self.filename)
+        self.assertEqual(metadata['~format'], 'OptimFROG DualStream Audio')
+
+
 cover_settings = {
     'embed_only_one_front_image': True,
 }