diff --git a/src/calibre/devices/usbobserver/usbobserver.c b/src/calibre/devices/usbobserver/usbobserver.c
index 8165332cd3..7268380e63 100644
--- a/src/calibre/devices/usbobserver/usbobserver.c
+++ b/src/calibre/devices/usbobserver/usbobserver.c
@@ -283,7 +283,11 @@ usbobserver_get_mounted_filesystems(PyObject *self, PyObject *args) {
 
     for (i = 0 ; i < num; i++) {
         val = PyUnicode_FromString(buf[i].f_mntonname);
-		if (!val) { NUKE(ans); goto end; }
+		if (!val) {
+            PyErr_Clear();
+            val = PyUnicode_DecodeLocale(buf[i].f_mntonname, "surrogateescape");
+            if (!val) { NUKE(ans); goto end; }
+        }
 		if (PyDict_SetItemString(ans, buf[i].f_mntfromname, val) != 0) { NUKE(ans); NUKE(val); goto end; }
         NUKE(val);
     }