Apple Calendar not working: what to check, in order

When the built in Calendar app on a Mac misbehaves, the reflex is to remove the account and add it back. Sometimes that works. Often it does nothing for the actual problem and wipes out shared calendar settings and per account alert defaults along the way, which then have to be rebuilt by hand.

Most Calendar problems that are not about sync delays fall into one of five symptoms, and Apple publishes a separate checklist for each. This piece sorts those checklists into the order that costs the least time, and points out the details that usually get missed.

Sort the symptom before touching anything

Apple's Calendar guide for Mac lists five troubleshooting topics:

• If you can't change a calendar or event
• If you don't see your events
• If you don't receive calendar alerts
• If people don't receive invitations sent from Calendar
• If you deleted iCloud calendars or events

A vague feeling that "Calendar is broken" nearly always maps to one of them. Picking the right one first cuts the search space to a fifth.

A quick way to sort:

1. The event is visible but will not change. That is symptom one.
2. The event cannot be found at all. Symptom two.
3. The event is there and editable, but nothing pops up at the time. Symptom three.
4. Everything looks fine locally, but the other person never got the invitation. Symptom four.
5. Something was deleted by mistake. Symptom five.

Removing and re adding an account belongs at the very end of every path, not the start.

Symptom one: an event that will not change

The time field is locked, or dragging the event does nothing. This is almost always a permissions question rather than a fault. Apple's guide lists the reasons plainly.

If you were invited to an event, you can change only some settings: your status, the calendar where the event appears, the alerts, and your availability. Source: support.apple.com

The same page gives several other causes:

• Events on subscribed calendars cannot be changed, though the calendar's name, colour, and alert settings can.
• Calendars shared with view only access cannot be edited.
• Birthdays on the Birthdays calendar are edited in Contacts, not in Calendar.
• If an event's time zone cannot be changed, time zone support may be turned off under Settings, then Advanced.
• If the email address used is missing from the Contacts card, Calendar may not treat the event as yours.

The order to check

Open the event and look at who organised it. If it is someone else, the time belongs to them and a change has to be requested.

If the event is yours and still locked, hover over the calendar's name in the sidebar and check its sharing status. A view only label means the owner needs to grant edit access.

If neither applies, open Contacts and confirm that the card marked as yours lists every address used for calendars. This last check is the one that gets skipped, and it also explains symptom four in many cases.

Symptom two: events that do not appear

An event added on a phone, or one that certainly existed yesterday, is not on screen. Before blaming sync, rule out display settings. Apple's list, reordered by effort:

• Is there a checkmark next to the calendar that holds the event?
• Is Show All Day Events checked in the View menu?
• If the event was declined, is View, then Show Declined Events turned on?
• Does searching for the event's title find it?
• Could a time zone difference be showing the event at another time?
• Are the Mac's date, time, and time zone correct in Date & Time settings?

The two that get missed

Time zones. If time zone support is on and a different zone is selected in the toolbar, every event shifts. An event that seems missing may be sitting several hours away, sometimes on the previous or next day.

Declined events. Once declined, an event leaves the default view. It has not been deleted.

Shared Google calendars that never show up

A related case: personal Google calendars appear, but a calendar a colleague shared does not. The fix sits on Google's side, not the Mac's. Google's help says to open the Calendar sync page on a computer, check the names of the calendars that should sync, and click Save. The same page adds that if Apple Calendar's Delegation tool was used for syncing, it needs to be turned off for Calendar sync to work.

Search is the dividing line

If search finds the event, the data is on the Mac and the problem is display settings. Only when search comes up empty does it make sense to look at the account itself and at sync, which is a separate set of checks.

Symptom three: alerts that never fire

Missing alerts are split between Calendar's own settings and macOS settings, which is why fixing one side often seems to do nothing. Apple lists six checks. One of them is easy to overlook entirely.

Make sure a Focus isn't active when you want to receive alerts. Source: support.apple.com

Grouped by where each setting lives:

Where to look	What to confirm
Calendar, Settings, Alerts	Alerts are not off, and default times for events, all day events, and birthdays are not set to None
System Settings, Notifications	Allow notifications is on for Calendar
Focus	No Focus is active at the time the alert should appear
The event itself	An alert is actually set on that event
Contacts	If the alert sends an email, the address on the card is correct

Alerts are set per account

The detail that explains most partial failures: default alert times are chosen separately for each account. When iCloud events alert and Google events do not, open Calendar, Settings, Alerts, switch the Account menu to the Google account, and check whether its defaults are None.

The same screen offers an option to use the default alerts on only this computer. If it is selected on one Mac and not another, the two machines will behave differently for the same account.

Scheduled Focus modes

A sleep Focus set to end at 9:00 will silence a 9:00 meeting alert. Scheduled Focus modes are easy to forget because they switch on without any action.

Time to leave alerts that never arrive

Sometimes the event alert fires, but the "time to leave" alert does not. That one follows different rules. Apple's guide says a time to leave alert is set when the event's info window includes a map. If a location is typed in and used as is, instead of being picked from the suggestion list, the map may not appear, and without the map there is no time to leave alert.

Three more rules apply:

• Location Services must be on in Privacy & Security settings, because the alert depends on the Mac's location.
• Destinations that take more than 3 hours to reach do not get a time to leave alert.
• Time to leave alerts for all events can be switched off in Calendar's Alerts settings.

Check in that order. Open the event and look for a map. If there is none, re-enter the location and pick it from the list. If the map is there and the alert still does not come, confirm Location Services and the Alerts setting. Travel time also does not update automatically when the location changes, so an edited location needs its travel time chosen again.

Symptom four: invitations the other side never receives

Attendees are listed on the event, but someone says the invitation never came. Apple's checklist, in order:

• Make sure the card in Contacts includes all of the sender's email addresses.
• Send a plain email to each invitee to confirm account settings and internet access are working.
• Confirm both sides have a working internet connection.
• If an event or shared calendar was changed, refresh calendars.
• For shared calendars, confirm the account information in Calendar's Accounts settings.

The first item carries most of the weight. People with a work address and a personal address often have only one on their Contacts card. An invitation sent from the other address may not register the sender as the organiser. When that happens, symptom one tends to appear at the same time.

The plain email test sounds trivial and is useful for exactly that reason. If the email arrives, the address is correct and the account can send. If it does not arrive, the problem is mail, not Calendar.

Symptom five: deleted iCloud calendars or events

A calendar was removed by mistake. For iCloud, Apple's guide says calendars and events can be restored on iCloud.com from an earlier version that iCloud archived automatically. Restoring first archives the current version, so the change can be reversed.

Restoring removes sharing. Apple notes that all sharing information is removed when calendars and reminders are restored, and everything has to be shared again. Before restoring, write down which calendars were shared and with whom.

This route only covers iCloud. Events deleted from a Google account are recovered through Google's own tools, so confirm which account heading the calendar sat under before starting.

Outside the five, and before deleting anything

One problem does not fit any of the five symptoms: invitations from strangers that keep landing on the calendar. Apple's guide describes a route for this. Double-click the event, click Report Junk, then delete it. According to Apple, the event is removed without notifying the sender.

Two lighter steps also belong before removing an account.

Refresh, and read the warning symbol

Choose View, then Refresh Calendars. If a shared, published, or subscribed calendar shows a warning symbol next to its name, Apple explains that Calendar could not connect to the calendar account. Check the internet connection, refresh again, and confirm the calendar has not been deleted or moved. Control-clicking the calendar and choosing Get Info shows its web address, which helps confirm where it is supposed to come from.

Turn the account off instead of deleting it

Choose Calendar, then Accounts, select the account, and deselect the Calendar checkbox. Its calendars and events disappear from Calendar on that Mac. Selecting the checkbox again brings them back. Unlike deletion, the account stays registered, so this is a safe way to test whether a symptom follows one account.

Deletion carries one more consequence worth knowing. For anyone using iCloud Keychain, Apple notes that removing an account other than the primary iCloud account prompts a choice between removing it from other Macs using iCloud Keychain or only turning off its features on this Mac. Reading that prompt carefully avoids breaking a second machine while fixing the first.

When fixing settings is not the whole story

Symptoms one and four come from the structure of ownership rather than from a broken setting. People who organise many meetings will keep meeting these checks. Guide walks through connecting accounts, inviting attendees, and handling meeting links in order.

Symptom three can also persist in a different form after alerts work again. An alert that fires exactly on time is still late if the event is across town. Travel time covers estimating the journey from an event's location and alerting at the moment to leave.

What to change first

Classify the problem into one of the five symptoms and run only that checklist, stopping before removing any account. If the same symptoms keep returning on a Google heavy calendar, a one week trial of Caltimate or another desktop calendar alongside the built in app is a low risk way to see whether the window itself is the issue.