diff --git a/R/list-transpose.R b/R/list-transpose.R
index 390101cb..5abcbaec 100644
--- a/R/list-transpose.R
+++ b/R/list-transpose.R
@@ -75,10 +75,15 @@ list_transpose <- function(x,
   if (length(x) == 0) {
     template <- integer()
   } else if (is.null(template)) {
-    template <- reduce(
-      map(x, vec_index),
-      vec_set_union,
-      error_call = caller_env()
+    indexes <- map(x, vec_index)
+    try_fetch(
+      template <- reduce(indexes, vec_set_union),
+      vctrs_error_ptype2 = function(e) {
+        cli::cli_abort(
+          "Can't combine named and unnamed vectors.",
+          arg = template
+        )
+      }
     )
   }
 
diff --git a/tests/testthat/_snaps/list-transpose.md b/tests/testthat/_snaps/list-transpose.md
index 92809b55..31d33924 100644
--- a/tests/testthat/_snaps/list-transpose.md
+++ b/tests/testthat/_snaps/list-transpose.md
@@ -69,6 +69,6 @@
     Code
       list_transpose(list(x = list(a = 1, b = 2), y = list(3, 4)))
     Condition
-      Error:
-      ! Can't combine `x` <character> and `y` <integer>.
+      Error in `handlers[[1L]]()`:
+      ! Can't combine named and unnamed vectors.