.ics files open in Calendar App instead of Microsoft Office Outlook


I did a Microsoft Office repair last week. Now when I click on a .ics file, It opens up in the Windows 10 Calendar App instead of Microsoft Outlook. When I went to change the default settings, I didn't see any options for Outlook like I did in my email default programs.


How do I fix it? I have Microsoft Office 365 on the Monthly Channel Insider program and regular Windows 10.

13 Replies



Having the same issue. No way to assign Outlook as the default app.

I found my Outlook was 1809 vs 1909. Went to File | Office Account | Office Updates and updated. Now I can open .ics files and assign outlook as the default app.

@tward60  my windows is the latest Windows 10 update.

I just want everyone to know that this issue resolved without me knowing what happened. Perhaps it was the midmonth Office 365 update that fixed it, but all ics. files now default to my Microsoft 365 Outlook instead of my Microsoft mail app.


Again, I can't explain specifically how this got fixed if anyone else is experiencing the same problem

@B_Van_Spanje The same thing has started happening to me. I've run the Outlook updates and it's still not resolved it. It is really annoying you can set O365 as the default opener for ics files not the Calendar app. 



Hi mate, was also headbutting the keyboard on this until...


Type default apps into search bar

Bottom left should be set default by apps

Find Calendar, click manage.

Change to Outlook on the .ics option.


Your welcome :D


I think I am having the same issue. my outlook is my default app but it keeps downloading a ics file like an attachment in an email instead of opening it as a calendar invite to "add to calendar"



I am a support tech and we have a Mac user with the same issue. The user gets invites all the time and adds them to her calendar via an ics file. Out of the blue last week Outlook just started opening the ics in an email message instead of her calendar.


Any news on a fix? She is up to date with Office for Mac 16.43

@RonBonham Having the same issue after the latest OS update. Having to open in iCal/Calendar and copy/paste into Outlook. 

The only work around I have found is to set the browser to save the file and not open it.  Then open Outlook and switch to Calendar mode.  Drag the file from File Explorer and drop on the calendar to add it.

All the usual methods to change this fail:

1. Open With - Outlook not listed, choosing Outlook gives you an error saying you can't open ics files with Outlook (lie)

2. Default Apps by File Type - Outlook not listed, no option to select a local app.

3. Registry hacks - haven't found one that works yet.

@B_Van_Spanje This is what I found on Mac help desk and it worked for me:   In Apple Calendar app, go to Calendar > Preferences and set Outlook as your default calendar. Thereafter, . ics files downloaded open automatically in Outlook


Please try the below for Windows 10 users, it may work for you:

Click on the start icon->type default apps->click on default apps->scroll to the bottom of the page->click on choose default apps by file type->scroll all the way down to .ics-> click on .ics and select outlook ->close outlook and reopen


@EJ100 As stated in the original reply, at the time the option to set the Default App for .ics files was not available to use as Outlook was not listed as a possible default app for .ics files, forcing it in also failed.


There was some fix applied a few weeks ago.  Not sure if it was Windows 10 or Office 365, but now .ics files open in Outlook again.  Probably Windows 10 as the default app for ics files can now be set to Outlook.