diff --git a/plinth/modules/email/data/etc/apache2/conf-available/email-freedombox.conf b/plinth/modules/email/data/etc/apache2/conf-available/email-freedombox.conf
index 9f99790de..f402a3cb3 100644
--- a/plinth/modules/email/data/etc/apache2/conf-available/email-freedombox.conf
+++ b/plinth/modules/email/data/etc/apache2/conf-available/email-freedombox.conf
@@ -28,3 +28,9 @@
         RewriteRule ^ /plinth/apps/email/config.xml [PT]
     </IfModule>
 </Location>
+
+# If Roundcube is not yet installed and the user clicks on 'Launch web client',
+# redirect to the installation page instead of Apache's Not Found page.
+<Location "/roundcube/">
+    ErrorDocument 404 /plinth/apps/roundcube/
+</Location>