diff --git a/src/vorta/borg/borg_thread.py b/src/vorta/borg/borg_thread.py
index 15aae39c..81a38791 100644
--- a/src/vorta/borg/borg_thread.py
+++ b/src/vorta/borg/borg_thread.py
@@ -42,9 +42,13 @@ class BorgThread(QtCore.QThread, BackupProfileMixin):
         self.app = QApplication.instance()
         self.app.backup_cancelled_event.connect(self.cancel)
 
-        extra_args = shlex.split(params.get('extra_borg_arguments', ''))
         cmd[0] = self.prepare_bin()
-        cmd = cmd[:2] + extra_args + cmd[2:]
+
+        # Add extra Borg args to command. Never pass None.
+        extra_args_str = params.get('extra_borg_arguments')
+        if extra_args_str is not None and len(extra_args_str) > 0:
+            extra_args = shlex.split(extra_args_str)
+            cmd = cmd[:2] + extra_args + cmd[2:]
 
         env = os.environ.copy()
         env['BORG_HOSTNAME_IS_UNIQUE'] = '1'
diff --git a/src/vorta/models.py b/src/vorta/models.py
index 53e5dda8..b0f39796 100644
--- a/src/vorta/models.py
+++ b/src/vorta/models.py
@@ -42,7 +42,7 @@ class RepoModel(pw.Model):
     unique_csize = pw.IntegerField(null=True)
     total_size = pw.IntegerField(null=True)
     total_unique_chunks = pw.IntegerField(null=True)
-    extra_borg_arguments = pw.CharField(default='', null=True)
+    extra_borg_arguments = pw.CharField(default='')
 
     def is_remote_repo(self):
         return not self.url.startswith('/')
@@ -332,4 +332,4 @@ def init_db(con):
         _apply_schema_update(
             current_schema, 12,
             migrator.add_column(RepoModel._meta.table_name,
-                                'extra_borg_arguments', pw.CharField(default='', null=True)))
+                                'extra_borg_arguments', pw.CharField(default='')))
diff --git a/src/vorta/views/extract_dialog.py b/src/vorta/views/extract_dialog.py
index a5728067..3a13fe07 100644
--- a/src/vorta/views/extract_dialog.py
+++ b/src/vorta/views/extract_dialog.py
@@ -13,9 +13,9 @@ uifile = get_asset('UI/extractdialog.ui')
 ExtractDialogUI, ExtractDialogBase = uic.loadUiType(uifile)
 ISO_FORMAT = '%Y-%m-%dT%H:%M:%S.%f'
 
-files_with_attributes = []
-nested_file_list = nested_dict()
-selected_files_folders = set()
+files_with_attributes = None
+nested_file_list = None
+selected_files_folders = None
 
 
 class ExtractDialog(ExtractDialogBase, ExtractDialogUI):
@@ -24,6 +24,11 @@ class ExtractDialog(ExtractDialogBase, ExtractDialogUI):
         self.setupUi(self)
         global files_with_attributes, nested_file_list, selected_files_folders
 
+        # Clear global file lists
+        files_with_attributes = []
+        nested_file_list = nested_dict()
+        selected_files_folders = set()
+
         def parse_line(line):
             size, modified, full_path = line.split('\t')
             size = int(size)
@@ -36,7 +41,7 @@ class ExtractDialog(ExtractDialogBase, ExtractDialogUI):
 
             return size, modified, name, dir
 
-        for l in fs_data.split('\n')[:-1]:
+        for l in fs_data.split('\n'):
             try:
                 files_with_attributes.append(parse_line(l))
             except ValueError: