diff --git a/R/arrays.R b/R/arrays.R
index 1482bb1c..01bb1ffd 100644
--- a/R/arrays.R
+++ b/R/arrays.R
@@ -50,7 +50,12 @@ array_branch <- function(array, margin = NULL) {
 
   if (length(margin) == 0) {
     list(array)
-  } else if (identical(as.integer(margin), 1L) && is.null(dim(array))) {
+  } else if (is.null(dim(array))) {
+    if (!identical(as.integer(margin), 1L)) {
+      stop(
+        "The passed array is 1D and does not have the margin(s) ",
+        toString(margin), call. = FALSE)
+    }
     as.list(array)
   } else {
     flatten(apply(array, margin, list))
diff --git a/tests/testthat/test-arrays.R b/tests/testthat/test-arrays.R
index ee01aefb..3f5a0a4d 100644
--- a/tests/testthat/test-arrays.R
+++ b/tests/testthat/test-arrays.R
@@ -15,6 +15,10 @@ test_that("array_branch works on vectors", {
   expect_identical(array_branch(1:3, 1), list(1L, 2L, 3L))
 })
 
+test_that("array_branch throws an error for wrong margins on a vector", {
+  expect_error(array_branch(1:3, 2), "does not have the margin\\(s\\) 2")
+})
+
 test_that("length depends on whether list is flattened or not", {
   m1 <- c(3, 1)
   m2 <- 3