diff --git a/src/calibre/gui2/linux_file_dialogs.py b/src/calibre/gui2/linux_file_dialogs.py
index 37d19dfec1..6b5f26c33b 100644
--- a/src/calibre/gui2/linux_file_dialogs.py
+++ b/src/calibre/gui2/linux_file_dialogs.py
@@ -28,7 +28,7 @@ def get_winid(widget=None):
 def detect_desktop_environment():
     de = os.environ.get('XDG_CURRENT_DESKTOP')
     if de:
-        return de.decode('utf-8', 'replace').upper()
+        return de.decode('utf-8', 'replace').upper().split(':', 1)[0]
     if os.environ.get('KDE_FULL_SESSION') == 'true':
         return 'KDE'
     if os.environ.get('GNOME_DESKTOP_SESSION_ID'):