diff --git a/du_setup.sh b/du_setup.sh
index d316f13..b4334db 100644
--- a/du_setup.sh
+++ b/du_setup.sh
@@ -700,7 +700,8 @@ cleanup_provider_packages() {
 
         else
             if confirm "Review and potentially remove root SSH keys?" "n"; then
-                local backup_file="$BACKUP_DIR/root_authorized_keys.backup.$(date +%Y%m%d_%H%M%S)"
+                local backup_file
+                backup_file="$BACKUP_DIR/root_authorized_keys.backup.$(date +%Y%m%d_%H%M%S)"
                 cp /root/.ssh/authorized_keys "$backup_file"
                 log "Backed up /root/.ssh/authorized_keys to $backup_file"