diff --git a/R/Rush.R b/R/Rush.R
index 0cdf7ee..81e39d0 100644
--- a/R/Rush.R
+++ b/R/Rush.R
@@ -397,6 +397,7 @@ Rush = R6::R6Class("Rush",
 
       if (length(lost_workers)) {
         running_tasks = self$fetch_running_tasks(fields = "worker_extra")
+        if (!nrow(running_tasks)) return(invisible(self))
         bin_state = redux::object_to_bin(list(state = "lost"))
         keys = running_tasks[lost_workers, keys, on = "worker_id"]
 
diff --git a/tests/testthat/test-Rush.R b/tests/testthat/test-Rush.R
index 44f2975..46121c7 100644
--- a/tests/testthat/test-Rush.R
+++ b/tests/testthat/test-Rush.R
@@ -539,6 +539,8 @@ test_that("a lost task is detected", {
   expect_data_table(data, nrows = 1)
   expect_set_equal(data$state, "lost")
 
+  expect_class(rush$detect_lost_tasks(), "Rush")
+
   pids = rush$worker_info$pid
   expect_rush_reset(rush)
   clean_test_env(pids)