diff --git a/build-aux/build-self.scm b/build-aux/build-self.scm
index c1a253dc87..87a45d94db 100644
--- a/build-aux/build-self.scm
+++ b/build-aux/build-self.scm
@@ -334,12 +334,13 @@ (define spin
                         (format (current-error-port)
                                 "Computing Guix derivation for '~a'...  "
                                 system)
-                        (let loop ((spin spin))
-                          (display (string-append "\b" (car spin))
-                                   (current-error-port))
-                          (force-output (current-error-port))
-                          (sleep 1)
-                          (loop (cdr spin))))
+                        (when (isatty? (current-error-port))
+                          (let loop ((spin spin))
+                            (display (string-append "\b" (car spin))
+                                     (current-error-port))
+                            (force-output (current-error-port))
+                            (sleep 1)
+                            (loop (cdr spin)))))
 
                       (match (command-line)
                         ((_ source system version protocol-version)