The following command entered in Terminal will enable the Debug menu in iCal (Lion):

defaults write com.apple.iCal IncludeDebugMenu YES

I would like to accomplish the same thing in Calendar (Mountain Lion).

  • 6
    Hmmm, interesting. The hook "IncludeDebugMenu" is not present in the Calendar binary like it was in the iCal binary. Also, thanks to iCloud, Calendar seems to do something different with defaults than iCal did. There are indeed some Debug Menu references in the binary, but they could just be vestigial from earlier versions of the program with no way to invoke them… This merits further exploration!
    – Daniel
    Aug 1, 2012 at 13:16

7 Answers 7


A menu is most desirable, so this is not a proper answer, but here goes …

Without the debug menu

It's possible to do at least some of the things that were possible with the menu.

Top sekret

Some of the things that were in the Top Sekret submenu of the Debug menu in iCal …

Days in week view

5 or 7 days: Use the General pane of Calendar preferences.

14, 21 or 28 days:

defaults write com.apple.iCal "n days of week" 14

defaults write com.apple.iCal "n days of week" 21

defaults write com.apple.iCal "n days of week" 28

The change will be effective when you next switch to week view.

New calendar window

+L is not effective. I'll investigate …

  • I like this answer: thank you. I really wanted the debug menu itself for other reasons (not looking for more days in my cal), but I think your answer should stay and be upvoted here in case other people are looking to do that.
    – Harv
    Aug 19, 2012 at 19:37
  • I did a little testing with fourteen days visible … suspect that some things may not work as expected (example: automatic presentation of an event after import from .ics). Aug 20, 2012 at 21:45
  • @Harv convenience of menus aside for a moment, can you achieve what you need without the Debug menu? If not, link to a question (or questions) detailing what you need. Thanks. Aug 22, 2012 at 7:12
  • Uh.. honestly I hoped that it would have a debugging feature that lets me see in detail what iCal is doing. I am having syncing issues and I suspect it might be coming from specific (corrupt?) events. I want to see what's happening inside iCal as it does a sync (and fails to sync specific events).
    – Harv
    Aug 23, 2012 at 3:35
  • @Harv please make it a question – describe the services and devices with which you sync – then link to the question. It should be answerable without the Debug menu. Thanks. Aug 30, 2012 at 16:57

I found this:

Show as Many or as Few Days as You Like in Mountain Lion Calendar

defaults write com.apple.iCal CalUIDebugDefaultDaysInWeekView <# OF DAYS>


I had Debug enabled in Lion, showing 2 weeks in iCal. Upgraded to Mountain Lion and could't get it back to one week view until I found Mountain Tweaks.

Under the Lion tab (not Mountain Lion) I clicked to disable iCal Debug and it worked. It's a free download but I donated to the developer.


Unfortunately this option seams to be gone forever, scan thought iCal's files from 10.7 gives two options that contain 'InsertDebugMenu'. However same scan on calendar's file from 10.8 doesn't show any of them, as a matter of fact this version is lacking more then few 'debug' commands that until this release were only hidden but still accessible. My worst nightmare is slowly coming true, OS X soon will be just as closed as iOS is already :/

In case someone with more time, skills or luck will read it, you can try find something on your own with help of this post.


The debug menu was great because it allowed you to display the CalDAV queue of events. Calendar under Mountain Lion is not fully compatible with MS Exchange and has a tendency to hang in "Updating…".

Worse, it gets into a mode where it cannot update the Exchange calendar at all and you must choose from a very DOS style "abort, retry, fail" sort of dialog. Once in that mode, your calendar will not talk to Exchange until you delete the Calendar's cache file. This Cache file apparently becomes corrupt and causes a discord between Calendar and Exchange.

Deleting the cache file is no issue as Calendar just rebuilds it when Calendar is launched again. Don't forget to Quit Calendar before deleting the cache file, then launch Calendar to have it automatically rebuild. No data is lost.

The Calendar cache file is located here:

~/Library/Calendars/Calendar Cache

This happens once or twice a day to me so I keep that folder in my dock and I keep an alias to the Calendar app in that folder so I can launch calendar, quit calendar, delete the cache file, launch calendar. Welcome to Mac OS X… (sigh)


OnyX is a great little program, and has an option to enable the debug menu for calendar.
Alternitively, you could try com.apple.Calendar IncludeDebugMenu YES in Terminal, although I’m not 100% sure it will work.

  • The option in OnyX doesn't work on Mountain Lion. The bundle identifier is still com.apple.iCal.
    – Lri
    Aug 10, 2012 at 12:03
  • oh. Well, never mind then. It was worth a shot
    – ash3r
    Aug 10, 2012 at 22:38

This isn't the answer you want, but I think the Debug option has really been disabled. However, I have filed a RADR to reinstate it in an upcoming dot increment (hopefully .2 or .3).

  • Can you link to it? If others are able to +1 it, maybe it'll get more attention and happen with more certainty, or sooner.
    – Harv
    Aug 18, 2012 at 20:35
  • @Harv The likeliest way of drawing Apple's attention to your own requirement is to send feedback to Apple. Incidentally I see nothing matching in Open Radar. Aug 18, 2012 at 22:15
  • Graham knows well that the methods some of us use to file reports do not appear in Open Radar, and we are asked to file only through our own channel. So, no, this cannot be +1ed, but it will receive attention, one way or the other.
    – ICL1901
    Aug 18, 2012 at 23:23
  • 1
    This is the submission: Follow-up #: Pending *SUBMISSIONID: F08D7334... *TYPE: ER *FROM: David Delmonte *PROJID: 1000624 *SEVERITY: high *REPRODUCIBILITY: Not Applicable *ORIGIN: Safari *TITLE: Restore Debug Menu for Calendar.app *SUMMARY: People are complaining that this capability is not available. Please consider restoring the menu. Alternatively, look at the options that the Debug menu allowed and add them into the app itself. *AREA: calendar *CONFIGURATION: *OS: Mac OS X *VERSION: 12A269 *HW: MacBook Air 1.8 GHz Intel Core i7 (MacBookAir4,2) RAM: 4 GB *NET: Wirelessly
    – ICL1901
    Aug 18, 2012 at 23:28

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