HelmStation Online Documentation
A chart subscription is an update service. When its term ends, the subscription has expired: HelmStation keeps the charts on your Mac and continues to display them, but they no longer receive corrections.
Expiry applies to charts from the HelmStation Store, including the NOAA Chart Service. Charts you added yourself in Chart Manager are never marked as expired, and neither are NOAA charts kept from a MacENCx64 registration. While Apple is retrying a failed renewal payment (Billing Issue in the Chart Account window), your charts are not treated as expired.
Expired charts are not safe to navigate by. From the day a subscription expires, your charts stop receiving the corrections that chart producers issue for new wrecks, moved or discontinued buoys and lights, changed depths and new restrictions. The longer a chart has been expired, the further it drifts from the real world.
HelmStation still shows expired charts so that your content isn’t taken away from you, not because they are fit for navigation. We do not recommend navigating on expired charts.
While any of your charts has expired, an amber Safety Warning link appears at the right end of the chart window’s toolbar, whether or not those charts are in view. Hover over it to see “Safety warning — you have expired charts. Click for details.” Click it to open the About Expired Charts window.
A yellow caution triangle appears at the top left of the chart, beside the chart’s own controls, whenever expired charts are showing in the view. It disappears when you move away from them. Hover over it to see “Expired charts are in view — their updates have stopped. Click to highlight them.” Click it and the expired charts in view flash, so you can see where they are.

In the list of charts in view, at the bottom right of the chart, each expired chart carries a small yellow triangle. Hover over it for the safety warning and “Update service ended” with the date. Clicking a chart’s row flashes it on the chart. See What the Chart Shows.

In File > Chart Manager, an expired chart’s catalog row has an amber warning triangle beside Catalog in the Object column. Hover over it for the safety warning and the date the update service ended. Click it to open About Expired Charts. See Chart Manager and Third-Party ENCs.

In File > HelmStation Chart Account, an expired subscription’s row is grayed out, shows Expired in the Subscription and Status columns, and gives its end date under Expires. See Chart Account and Delivery.
About Expired Charts explains what expiry means, in four sections: Safety Warning, Your Charts Remain, Which Charts Are Expired and Resuming Updates. Under Which Charts Are Expired it lists each of your expired charts with the date its update service ended.

Kept. Expiry never deletes charts. On each Mac where they are installed, your expired charts stay, with the last editions and corrections you received, and continue to display. Deauthorizing a Mac doesn’t remove them either: it affects only charts with active subscriptions. See Devices and New Macs.
Removed. HelmStation Store charts, expired or not, are removed in these cases:
We can deliver chart content to your Macs only while a subscription is active. Once it has expired, we can’t restore the charts for you, and Restore Subscription Purchases brings back only active subscriptions. If an expired chart is deleted, or the Mac it’s on is lost or damaged, you may not be able to get it back.
To protect expired charts you want to keep, back up your Mac regularly with Time Machine. Time Machine backs up HelmStation’s data, including your charts, and restoring it to the same Mac brings your expired charts back.
Moving to a new or different Mac is another matter:
Keep your old Mac until you’re sure you no longer need its expired charts. See Devices and New Macs.
To start receiving updates again, buy a new term in the HelmStation Store. Open HelmStation Store in the About Expired Charts window takes you there, and an expired chart’s row shows its price again.
After you buy, HelmStation delivers the latest editions to your authorized Macs. The warnings clear once HelmStation has synced the renewed subscription. To sync straight away, click Sync Now in File > HelmStation Chart Account. See HelmStation Store.