diff --git a/mu4e/mu4e-proc.el b/mu4e/mu4e-proc.el
index 2c4c0fb5..5754daf5 100644
--- a/mu4e/mu4e-proc.el
+++ b/mu4e/mu4e-proc.el
@@ -65,14 +65,15 @@ the length (in hex).")
 			       (list (concat "--muhome=" mu4e-mu-home))))))
     (setq mu4e~proc-buf "")
     (setq mu4e~proc-process (apply 'start-process
-			 mu4e~proc-name mu4e~proc-name
-		       mu4e-mu-binary args))
+			      mu4e~proc-name mu4e~proc-name
+			      mu4e-mu-binary args))
     ;; register a function for (:info ...) sexps
-    (when mu4e~proc-process
-      (set-process-query-on-exit-flag mu4e~proc-process nil)
-      (set-process-coding-system mu4e~proc-process 'binary 'utf-8-unix)
-      (set-process-filter mu4e~proc-process 'mu4e~proc-filter)
-      (set-process-sentinel mu4e~proc-process 'mu4e~proc-sentinel))))
+    (unless mu4e~proc-process
+      (mu4e-error "Failed to start the mu4e backend"))
+    (set-process-query-on-exit-flag mu4e~proc-process nil)
+    (set-process-coding-system mu4e~proc-process 'binary 'utf-8-unix)
+    (set-process-filter mu4e~proc-process 'mu4e~proc-filter)
+    (set-process-sentinel mu4e~proc-process 'mu4e~proc-sentinel)))
 
 (defun mu4e~proc-kill ()
   "Kill the mu server process."
@@ -275,18 +276,18 @@ terminates."
 	(cond
 	  ((eq code 9) (message nil))
 	    ;;(message "the mu server process has been stopped"))
-	  (t (mu4e-message (format "mu server process received signal %d" code)))))
+	  (t (error (format "mu server process received signal %d" code)))))
       ((eq status 'exit)
 	(cond
 	  ((eq code 0)
 	    (message nil)) ;; don't do anything
 	  ((eq code 11)
-	    (mu4e-message "Database is locked by another process"))
+	    (error "Database is locked by another process"))
 	  ((eq code 19)
-	    (mu4e-message "Database empty; try indexing some messages"))
-	  (t (mu4e-message "mu server process ended with exit code %d" code))))
+	    (error "Database empty; try indexing some messages"))
+	  (t (error "mu server process ended with exit code %d" code))))
       (t
-	(mu4e-message "Something bad happened to the mu server process")))))
+	(error "Something bad happened to the mu server process")))))
 
 (defun mu4e~proc-send-command (frm &rest args)
   "Send as command to the mu server process; start the process if needed."
diff --git a/mu4e/mu4e-utils.el b/mu4e/mu4e-utils.el
index 8d41b0e9..067a1287 100644
--- a/mu4e/mu4e-utils.el
+++ b/mu4e/mu4e-utils.el
@@ -525,9 +525,10 @@ process."
 
 (defun mu4e-error-handler (errcode errmsg)
   "Handler function for showing an error."
+  ;; don't use mu4e-error here; it's running in the process filter ctx
   (case errcode
-    (4 (mu4e-error "No matches for this search query."))
-    (t (mu4e-error "Error %d: %s" errcode errmsg))))
+    (4 (error "No matches for this search query."))
+    (t (error "Error %d: %s" errcode errmsg))))
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 
@@ -625,7 +626,6 @@ FUNC (if non-nil) afterwards."
       ;; better to check for specific features
       (unless (>= emacs-major-version 23)
 	(mu4e-error "Emacs >= 23.x is required for mu4e"))
-
       ;; set up the 'pong' handler func
       (lexical-let ((func func))
 	(setq mu4e-pong-func