diff --git a/tacc.el b/tacc.el
index a867201..8c1932e 100644
--- a/tacc.el
+++ b/tacc.el
@@ -155,6 +155,8 @@
 (define-error 'tacc-error "Generic error from the tacc-timer module" 'error)
 (define-error 'tacc-error-illegal-buffer-state
   "Precondition failed, the timer buffer is in an invalid state" 'tacc-error)
+(define-error 'tacc-dirty-state
+  "Precondition failed, tacc state wasn't clean" 'tacc-error)
 (define-error 'tacc-error-serialization-registered
   "Failed to register a serialization, serializations must have unique names"
   'tacc-error)
@@ -332,22 +334,22 @@ Note, if there is no tacc-buffer then you shouldn't be touching tacc-info"
           (if (tacc-live-state?)
               t
             ;; Timer running without reason in logic
-            (signal 'tacc-error-illegal-buffer-state (tacc-buffer)))
+            (signal 'tacc-error-illegal-buffer-state tacc-timer))
         (if (tacc-session-state?)
             t
           ;; Buffer is live without reason in logic
           (signal 'tacc-error-illegal-buffer-state (tacc-buffer))))
     ;; We shouldn't be calling this when the buffer is dead
-    (signal 'tacc-error-illegal-buffer-state (tacc-buffer))))
+    (signal 'tacc-error-illegal-buffer-state "No buffer")))
 
 (defun tacc-cleanup-invariant ()
   "Returns t if tacc is in a cleaned up state, signals an error otherwise"
   (if (bufferp (tacc-buffer))
-      (signal 'tacc-dirty-state (tacc-buffer))
+      (signal 'tacc-error-dirty-state (tacc-buffer))
     (if (tacc-live?)
-        (signal 'tacc-dirty-state tacc-timer)
+        (signal 'tacc-error-dirty-state tacc-timer)
       (if (tacc-session?)
-          (signal 'tacc-dirty-state tacc-info)
+          (signal 'tacc-error-dirty-state tacc-info)
         t))))
 
 ;; 05.3 Predicates and helpers