diff --git a/src/cuirass/remote-server.scm b/src/cuirass/remote-server.scm
index 6c946737014d7c8a8652ed99a682c562a6c99fc0..a5b56e4cc084703c13297bf4fab9941af891c74e 100644
--- a/src/cuirass/remote-server.scm
+++ b/src/cuirass/remote-server.scm
@@ -426,6 +426,9 @@ exiting."
   (setvbuf (current-output-port) 'line)
   (setvbuf (current-error-port) 'line)
 
+  ;; Use a default locale.
+  (setlocale LC_ALL "en_US.utf8")
+
   (with-error-handling
     (let* ((opts (args-fold* args %options
                              (lambda (opt name arg result)
diff --git a/src/cuirass/remote-worker.scm b/src/cuirass/remote-worker.scm
index 69ccf023fbde61456e2b4d9fc9caacfb1c61f8e7..efbb9c71c7cad24192d0ea3c4d9e72ecaaf4ea87 100644
--- a/src/cuirass/remote-worker.scm
+++ b/src/cuirass/remote-worker.scm
@@ -350,6 +350,9 @@ exiting."
   (setvbuf (current-output-port) 'line)
   (setvbuf (current-error-port) 'line)
 
+  ;; Use a default locale.
+  (setlocale LC_ALL "en_US.utf8")
+
   (with-error-handling
     (let* ((opts (args-fold* args %options
                              (lambda (opt name arg result)