My subscribed calendar is a day behind. Is it broken?

Not necessarily. Microsoft says updates can take more than 24 hours.

I imported a calendar and nothing updates.

That is how import works: Microsoft calls it a snapshot. If you need later updates, subscribe to the publisher’s current feed and verify it first. Only then identify and deliberately remove any unwanted imported copies; do not delete unrelated events from the destination calendar.

All articles

Add an internet calendar to Outlook: subscribe for updates or import a snapshot

A link to a school or club calendar can be added to Outlook in two ways, and only one keeps up with changes. Even that one is not instant. Arte Soft, the developer of Cloud Calendars, explains what Microsoft documents for Outlook.com and Outlook on the web.

Subscribe or import

	Subscribe from web	Upload from file (import)
Gets later changes	Yes	No
Typical refresh (Microsoft)	Outlook.com ~3 h; Outlook on the web ~6 h; can exceed 24 h	Never
Where events go	A separate subscribed calendar	A calendar you choose
Best for	Calendars that change	Fixed dates

What most people assume

A subscribed calendar updates as soon as the publisher changes it.

Snapshot or connection

Microsoft explains that importing an .ics file gives you a snapshot of the events at the time of import; your calendar doesn’t refresh them even if the owner updates the calendar. It suggests import for things that won’t change, like tide tables or moon phases.

Subscribing connects the online calendar to yours, and Outlook updates it when the owner changes events. Microsoft suggests subscribing for things that change, like a school calendar.

How long updates take

Microsoft gives different figures for the two web clients. For Outlook.com (personal accounts), it says updates should happen approximately every 3 hours but can take more than 24 hours. For Outlook on the web (work or school), it says approximately every 6 hours, and also more than 24 hours at times.

Treat these as Microsoft’s typical figures, not deadlines. For a same-day change, check the publisher’s site or ask the organiser.

Steps

In Calendar, choose Add calendar. To subscribe, choose Subscribe from web, enter the URL and select Import (Outlook.com) or Import and Save (Outlook on the web). To import, choose Upload from file, pick the .ics file, choose which calendar it goes into, and select Import; Microsoft’s work/school instructions also show Save.

Microsoft suggests that if subscribing fails, you can import instead — accepting that you lose updates. Its instructions for classic Outlook on the web also mention removing an empty internet calendar and re-adding its URL with https rather than http. That is a legacy web-client troubleshooting note, not a desktop Outlook command; use the publisher’s valid HTTPS feed address rather than inventing an address.

Worked example: a school term calendar

A fictional parent receives two things from a school: a link ending in .ics for the term calendar, and a one-off .ics file for sports day. They add the link with Subscribe from web so term changes arrive, and upload the sports-day file into their own Family calendar.

When the school moves an inset day on a Monday morning, the parent’s Outlook still shows the old date at lunchtime. Such a delay is consistent with Microsoft’s figures; they check the school website and adjust plans. The imported sports-day entry does not follow subsequent changes from the school.

Check: the subscribed calendar appears as its own calendar in the list; the imported event sits inside Family.

What it looks like

Cloud Calendars overview, using our product images. Provider settings and protocol examples described in this guide are separate from the screens shown here.

What to do

Use Subscribe from web for a link to a changing calendar.
Use Upload from file for a fixed set of dates.
Expect hours, sometimes more than a day, before changes appear.
If a subscription is empty, verify the publisher’s current feed address and whether HTTPS is supported before changing or reconnecting it.
Confirm urgent changes at the source.

Questions

My subscribed calendar is a day behind. Is it broken?: Not necessarily. Microsoft says updates can take more than 24 hours.
I imported a calendar and nothing updates.: That is how import works: Microsoft calls it a snapshot. If you need later updates, subscribe to the publisher’s current feed and verify it first. Only then identify and deliberately remove any unwanted imported copies; do not delete unrelated events from the destination calendar.