diff --git a/bootfiles/18e/boot26.lisp b/bootfiles/18e/boot26.lisp
new file mode 100644
index 0000000000000000000000000000000000000000..afb20020d0cd097fb2a3a33246c45c51b7075c75
--- /dev/null
+++ b/bootfiles/18e/boot26.lisp
@@ -0,0 +1,6 @@
+(in-package :cl-user)
+
+(ext:without-package-locks
+ (unintern 'lisp::simple-stream-error :lisp)
+ (unintern 'conditions::simple-stream-error :conditions)
+ (export 'kernel::simple-stream-error :kernel))