diff --git a/knots/resource-pool.scm b/knots/resource-pool.scm
index 17919a6..ac536cc 100644
--- a/knots/resource-pool.scm
+++ b/knots/resource-pool.scm
@@ -341,7 +341,14 @@
                      start
                      (cdr end))))
 
-                (loop (remove-at-index! resources index)
+                (loop (if index
+                          (remove-at-index! resources index)
+                          (begin
+                            (simple-format
+                             (current-error-port)
+                             "resource pool error: unable to remove ~A\n"
+                             resource)
+                            resources))
                       available   ; resource shouldn't be in this list
                       waiters
                       (remove-at-index!