Index: openacs-4/packages/acs-lang/tcl/locale-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-lang/tcl/locale-procs.tcl,v
diff -u -r1.51.2.11 -r1.51.2.12
--- openacs-4/packages/acs-lang/tcl/locale-procs.tcl	26 Nov 2021 13:10:01 -0000	1.51.2.11
+++ openacs-4/packages/acs-lang/tcl/locale-procs.tcl	28 Feb 2022 17:41:09 -0000	1.51.2.12
@@ -568,10 +568,10 @@
         set locale [lang::system::site_wide_locale]
     }
 
-    # if that does not exist then we are back to just another language
-    # let's pick uhmm... en_US
+    # if that does not exist, or is not supported, then we are back to
+    # just another language let's pick uhmm... en_US
 
-    if { $locale eq "" } {
+    if { $locale eq "" || $locale ni [lang::system::get_locales]} {
         set locale en_US
     }