diff --git a/configure/tools/convertRelease.pl b/configure/tools/convertRelease.pl
index 07547b061..7b3638d0b 100755
--- a/configure/tools/convertRelease.pl
+++ b/configure/tools/convertRelease.pl
@@ -42,7 +42,7 @@ $top = $cwd;
 #$top =~ s/^\/cygdrive\/(\w)\//$1:\//;
 $top =~ s/\/iocBoot.*$//;
 $top =~ s/\/configure.*$//;
-if ($^0 eq "cygwin") {
+if ($^O eq "cygwin") {
   chomp($top = `cygpath -m $top`);
 }