Itsycal not working: what to check, in order

Itsycal is a free menu bar calendar for the Mac, made by the independent developer Mowglii, and most of the time it "stops working" without being broken at all. It has no accounts and no sync of its own. It reads the calendars already set up in the Mac Calendar app and shows them in a small dropdown, so a blank agenda or a missing icon usually traces back to System Settings, the Calendar app, or the wrong build for the installed macOS. As of 18 October 2026 the official download page offers two builds: the latest version for macOS 27 and later, and version 0.15.15 for macOS 11 and later. Installing the build that does not match the Mac is now one of the first things to rule out. This guide lists the checks in the order that wastes the least time, with each fix tied to the developer's own help page or version history.

What Itsycal is, and why that sets the check order

The project README on GitHub describes the app in one line: a tiny calendar for the Mac menu bar, meant as a companion to the Mac Calendar app, that can create and delete events but not edit them (sfsam/Itsycal on GitHub). The code is published under the MIT license. The developer's About page states that the apps are free and that donations are optional (Mowglii About).

That design decides where problems come from. An event has to pass four points before it reaches the dropdown:

Point	Where it is controlled	What breaks when it fails
Account	System Settings, Internet Accounts, or the Calendar app	The event is missing everywhere on the Mac
Permission	System Settings, Privacy and Security, Calendars	Calendar shows the event, Itsycal shows nothing
Calendar selection	Itsycal Settings, General tab	Some calendars appear, others do not
Display options	Itsycal Settings, General and Appearance tabs	Empty agenda, odd week numbers, wrong first weekday

The quickest single test is to open the Calendar app. If the event is not there, nothing inside Itsycal will make it appear, and the fix is on the account. If the event is there, the cause is almost always permission or the calendar checkboxes.

Reinstalling rarely helps for the same reason. Preferences are stored outside the app bundle under the identifier com.mowglii.ItsycalApp, so a fresh copy reads the same settings as the old one.

Step one: confirm the right build for the installed macOS

The download page now splits into two lines (Itsycal for Mac):

Build on the official page	Supported macOS	Notes from the version history
Itsycal (latest), 0.27.x	macOS 27 and later	0.27.0 updated the look for macOS 27 Golden Gate. 0.27.3 worked around a macOS 27 date formatter bug
Itsycal 0.15.15	macOS 11 and later	Last of the 0.15 line. Showing Itsycal in the upper right when a menu bar manager hides it
Itsycal 0.14.1	macOS 10.14 and later	For older Macs
Itsycal 0.11.17, 0.10.16, 0.8.15	macOS 10.12, 10.10, 10.8	Archived builds

The version history lists all of these (Itsycal version history). Two practical consequences follow.

First, a Mac that moved to macOS 27 and is still running a 0.15 build may show date or formatting problems that 0.27.3 addresses. The 0.27.3 entry reads, in full, "Worked around macOS 27 date formatter bug."

Second, package managers can lag behind. On 18 October 2026 the Homebrew cask for Itsycal listed version 0.15.14, while the official page offered 0.15.15 and the 0.27 line (Homebrew cask). Anyone who installed through Homebrew should compare the version under the gear menu with the official page before reporting a bug.

The official page credits the Sparkle framework, the common Mac library for in-app updates. A build installed by hand or by a package manager should still be compared with the version history now and then, since old bugs stay until the build changes.

The icon is missing from the menu bar

A missing Itsycal is usually still running. The help page gives two causes, and neither is a crash (Itsycal Help).

The menu bar is full

When the menu bar runs out of room, macOS hides new items with no warning. A MacBook notch takes the middle of the bar and makes this far more likely. Quit two or three other menu bar apps and see whether the date returns. Once it does, hold Command and drag the icon toward the right side of the bar, which the help page recommends so it is less likely to be hidden again.

macOS blocks it

On macOS 26 Tahoe and later, System Settings has a Menu Bar panel where each app can be allowed or hidden. If Itsycal is switched off there, freeing space changes nothing.

Menu bar managers

Apps such as Ice that collapse menu bar items have a history with Itsycal. Version 0.15.11 changed how Itsycal positions itself when space is short or a hiding app is in use. Version 0.15.12 reverted that change because it broke behavior with macOS menu bar auto hiding. Version 0.15.15 added a different answer: if a menu bar manager or a long application menu hides Itsycal, opening it with the keyboard shortcut shows it in the upper right of the screen. The 0.27.1 release went further with a setting to always show Itsycal in the top right corner instead of anchoring it to the icon. Assigning a shortcut under Settings, General, Keyboard shortcut is therefore the most reliable way to reach the calendar on a crowded bar.

Events do not appear

Work through the four points in order.

The account

If the event is missing from the Calendar app as well, add or repair the account in System Settings under Internet Accounts, or in Calendar itself. Apple's guide covers adding iCloud, Google, and other CalDAV accounts (Apple Support).

Delegate calendars are a known gap. The help page says Itsycal cannot show delegate calendars directly. For Google, the workaround is to select those calendars in Google Calendar's sync settings and save, after which they appear as ordinary calendars in the Calendar app and then in Itsycal.

The permission

If Calendar shows the event and Itsycal does not, open System Settings, then Privacy and Security, then Calendars, and confirm that Itsycal has access. Without it the agenda stays empty however the app is configured.

The checkboxes

Open Settings from the small gear icon below the calendar and go to the General tab. The help page explains that every calendar set up in the Calendar app is listed there, and only checked calendars are tracked. After adding an account, look at this list again: any calendar left unchecked stays out of the agenda.

A forced refresh

After a change on another device, Option, Command and R refreshes events, according to the keyboard shortcut list on the help page. Pressing the period key toggles event locations in the agenda, which is worth knowing if locations seem to have vanished.

Events cannot be edited, or new ones go to the wrong calendar

The most common complaint is not a bug. The README is explicit that Itsycal creates and deletes events but does not edit them. Changes to time, guests, or notes happen in the default calendar app, which Command and O opens from inside Itsycal.

The default calendar for new events

Itsycal has no default calendar of its own. The help page says it honors the default calendar set in the Mac Calendar app's General settings. If work meetings keep landing on a personal calendar, change the default there.

Event length

Since 0.15.11, a new event uses the default duration set in the Calendar app. Earlier builds always used one hour. A Mac still on an older build shows the old behavior.

Opening a different calendar app

The help page confirms that Itsycal's calendar button can open BusyCal or Fantastical instead of Apple Calendar. The method is to set that app as the default calendar app in Calendar, under Settings, then General. The page notes that a macOS bug sometimes stops this from sticking and links to a community workaround.

Meeting links

Command and J opens the first active virtual meeting in the agenda. Version 0.27.2 added a "Copy Meeting Link" item to the right click menu for events that carry one. On a 0.15 build that item does not exist, which can look like a missing feature.

Dates, week numbers, or the first weekday look wrong

Dates

The help page states that Itsycal supports only the Gregorian calendar, and dates will be wrong with another system such as the Buddhist calendar. Check System Settings, Language and Region.

Week numbers

Itsycal follows ISO 8601 in the week column beside the month grid. The menu bar text is drawn by macOS, which does not follow ISO 8601 by default, so three different week numbers can appear: in the grid, in the menu bar, and in Apple Calendar. The help page's fix is to change the calendar in Language and Region from Gregorian to ISO 8601. Version 0.13.2 also made custom menu bar date patterns follow ISO 8601 automatically, and 0.15.7 worked around a macOS Sequoia issue with the EEE weekday pattern under ISO 8601.

First day of week

By default Itsycal uses the locale's convention, Sunday in the US and Monday in much of the world. The First day of week popup in the General tab overrides it.

Crashes, high CPU, and hidden settings

Crashes after a macOS upgrade

The best documented case is macOS Ventura. In a post dated 5 November 2022, the developer reported that most crash reports came from people with non iCloud calendar accounts. The suggested fix is to open System Settings, Internet Accounts, remove and re-add every non iCloud account, then launch Itsycal (Mowglii blog). The cause, per the post, was macOS returning no valid account name for some providers at launch. Removing an account takes its events off the Mac until they download again.

CPU and memory

Version 0.15.7 introduced excessive CPU use, fixed in 0.15.8. A memory leak on macOS 26 Tahoe was fixed in 0.15.9. Both point to the same first step: check the version before anything else.

Hidden preferences set in Terminal

Several options exist only as defaults commands in the version history, such as ShowEventPopoverOnHover for event details on hover, DoNotDrawOutlineAroundCurrentMonth, and EnableTahoeMenuIcons to bring menu icons back on macOS 26. A setting applied months ago and forgotten can look like a new bug. Running defaults read com.mowglii.ItsycalApp in Terminal lists what is set.

Reporting a bug

The About page asks for the Itsycal version, the macOS version, and the Mac's model, year, and chip type, plus a crash report if there is one. Reading the help page first is requested, since it usually answers faster than email.

When the check list passes and Itsycal still does not fit

If every point checks out and the frustration remains, the problem is scope rather than failure. Itsycal is built to glance at a schedule; editing, invitations, and planning around travel happen in whatever app sits behind it. Other menu bar calendars sit at different points. Dato, for example, is listed at $18 as a one time purchase and requires macOS 26 or later, per its developer's page checked on 18 October 2026 (Dato). Full calendar apps for the Mac cover editing and scheduling inside one window, and the comparison page sets several of them side by side by price and features.

What to change first

Check the build against the installed macOS, then open the Calendar app and see whether the missing event is there. Those two checks resolve most reports. If the real need turns out to be editing and planning rather than glancing, see how a desktop calendar such as Caltimate handles typed entry and travel time.