diff --git a/acme.sh b/acme.sh
index 0b0f3ce9..ecea7bc2 100755
--- a/acme.sh
+++ b/acme.sh
@@ -7011,7 +7011,9 @@ installcronjob() {
     #failure must abort: piping an incomplete list back into 'crontab -'
     #would wipe the user's existing cron jobs (issue 3079)
     _cron_list_err="$($_CRONTAB -l 2>&1 >/dev/null)"
-    if echo "$_cron_list_err" | grep -i "no crontab\|no fcrontab\|can't open" >/dev/null; then
+    #multiple -e instead of \| : BRE alternation is a GNU extension that
+    #BSD grep does not support
+    if echo "$_cron_list_err" | grep -i -e "no crontab" -e "no fcrontab" -e "can't open" >/dev/null; then
       _cron_entries=""
     else
       _err "Can not list the current cron jobs: $_cron_list_err"