The deployed /etc/cron.d/download-virtio-win never ran. It omitted the user
field that /etc/cron.d entries require between the schedule and the command,
so cron parsed the script path as a username, and its day-of-month field was
0, outside the valid range of 1-31.
Corroborated on the host: the newest ISO is virtio-win-0.1.285 from
2025-09-20, the same day the cron file was created.
Pass --cron so a no-op run emits no progress bar and generates no cron mail.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>