R-1253 (P2): an export that stops its app refuses while another operation (a restore) holds the app-stop marker — its Undo is never replaced. Commit only.

controller/internal/i18n/locales/en.json

@@ -1250,6 +1250,7 @@
   "err.after_start.failed": "Saving did not work. Try again.",
   "err.backup.restore_drive_gone": "The drive “%s” cannot be reached, so the restore could not start. Connect the drive again, then start the restore again.",
   "err.stacks.remove_keep_data_while_support": "While support is working on this app, its data cannot be deleted — you can remove the app and keep its data.",
+  "err.appexport.another_operation_running": "Another operation (for example a restore) is holding an app stopped now, so an export that stops the app cannot start. Try again when that operation has finished.",
   "err.appexport.a_mentes_nem_tartalmaz_alkalmazasadatot_0": "the backup holds no app data (0 data folders, 0 volumes for an app that stores data)",
   "err.appexport.a_z_adatkonyvtar_tartalma_hianyzik_a": "the contents of data folder %q are missing from the package",
   "err.appexport.a_z_kotet_adata_hianyzik_a": "the data of volume %q is missing from the package",