diff --git a/src/bin/pg_basebackup/t/020_pg_receivewal.pl b/src/bin/pg_basebackup/t/020_pg_receivewal.pl
index 17fd71a450..158f7d176f 100644
--- a/src/bin/pg_basebackup/t/020_pg_receivewal.pl
+++ b/src/bin/pg_basebackup/t/020_pg_receivewal.pl
@@ -72,11 +72,13 @@ $primary->command_ok(
 my @partial_wals = glob "$stream_dir/*\.partial";
 is(scalar(@partial_wals), 1, "one partial WAL segment was created");
 
-# Check ZLIB compression if available.
+# Check ZLIB compression if available.  On Windows, some old versions
+# of zlib can cause some instabilities with this test, so disable it
+# for now.
 SKIP:
 {
-	skip "postgres was not built with ZLIB support", 5
-	  if (!check_pg_config("#define HAVE_LIBZ 1"));
+	skip "postgres was not built with ZLIB support, or Windows is involved", 5
+	  if (!check_pg_config("#define HAVE_LIBZ 1") || $windows_os);
 
 	# Generate more WAL worth one completed, compressed, segment.
 	$primary->psql('postgres', 'SELECT pg_switch_wal();');