Share via

Outlook "not supported calendar message.ics"

Anonymous
2024-05-15T15:21:31+00:00

I am sending an email from my application's API to a customer. I am attaching an ICS file that meets RFC 5545 standards. I have verified this through the validator located at https://icalendar.org/validator.html. 

Outlook always renames the attachment "not supported calendar message.ics". I can open it and it does prompt me to create the event with the correct information filled in.

My question is why does it say it is not supported? Even though it technically "works", a customer is going to see that and get confused.

Gmail and iOS mail don't seem to have any issues with the ICS file.

I even tried to create an event in Outlook itself and save it as an ICS file. Even that files comes through Outlook as not supported when I send it as an attachment to an email.

Any advice would be greatly appreciated. Thanks

Outlook | Windows | New Outlook for Windows | For home

Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

0 comments

9 answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. Anonymous
    2024-05-16T22:39:21+00:00

    It's not a reoccurring event.

    I think it's pretty obvious at this point that Microsoft Outlook does not conform to the iCalendar standard. Other clients do not seem to have an issue with it.

    6 people found this answer helpful.
    0 comments
  2. Anonymous
    2024-06-25T15:34:09+00:00

    We are having the same issues. Commenting in case this case gets solved.

    4 people found this answer helpful.
    0 comments
  3. Anonymous
    2024-05-16T19:16:09+00:00

    Dear JohnMcComas

    Thanks for your response!

    The "not supported calendar message.ics" attachment is created when the original .ics file cannot be converted to an Outlook or Microsoft Exchange meeting type. The conversion fails if one or more of the following conditions are true:

    1. The meeting contains a recurrence pattern that is available to a third-party email client, such as Lotus Notes. However, this recurrence pattern is not supported by Outlook:
      • Monthly by Date: Every month on the nth day and the nth day. Outlook only supports one nth day of the month.
      • Monthly by Day: Every month on the nth day of the week and the nth day of the week. Outlook only supports one nth day of the week in any month.
      • Custom recurrence: Outlook does not support custom recurrence patterns that are available in some third-party email clients, such as Lotus Notes.
    2. The meeting contains a recurrence pattern that is defined by the RDATE property. However, the meeting does not include a corresponding RRULE property. In this case, Outlook does not open the item, even if the RDATE property specifies a supported recurrence pattern

    For more info and workaround, you can refer to Outlook receives a message that has an attachment that is named "not supported calendar message.ics" - Microsoft Support.

    On the other hand, if you are using Exchange account, you may have a try to open ICS File with Windows Calendar.

    1. You need to save the "not supported calendar message.ics" file on the desktop pf upir ,acjome.
    2. After that, right-click on the same file and select Open With > Calendar option.
    3. Here, it will ask you "Which calendar would you like to add these events to?". Simply, choose Exchange Calendar.
    4. Then, click on the Add to calendar button
    5. Now, wait for a few minutes, this meeting is added to your Calendar in Outlook.

    Note: This meeting is added in Appointments and first occurrence of meeting might be added twice in the Calendar.

    Thanks for your precious time and your understanding would be highly appreciated. Have a nice day!

    Sincerely,

    Allen | Community Moderator

    1 person found this answer helpful.
    0 comments
  4. Anonymous
    2024-05-16T13:09:32+00:00

    I can send the emails just fine. The issue is on the receiver's end. The ICS attachment appears as an attachment named "not supported calendar message.ics".

    The issue appears on both the desktop Outlook Client (2404). It also appears on the web client at outlook.office365.com/.

    I am not trying to convert the ICS file at all. I am using a plain text file and saving it with a .ics extension.

    The accounts that I am testing it with are Exchange accounts (work and personal).

    The ics file is being sent as a separate file attachment.

    Thanks

    0 comments
  5. Anonymous
    2024-05-15T15:59:55+00:00

    Dear JohnMcComas Good day!Thank you for posting to Microsoft Community. We are glad to assist! Based on your description, I understand you concern with  unable to send emails with attaching an ICS file. To narrow down your issue, could you please allow me to collect more details?

    May I know whether you have the same issue in Outlook on the web?

    May I know what version of Outlook you are using What version of Outlook do I have? - Microsoft Support? Please make sure that you are using the latest version of Outlook.

    May I know whether you have tried converting the ICS file to a different format such as CSV or VCS and then attaching it to the email?

    May I know what account type you are using? Is it POP, IMAP or Exchange account?

    In the meanwhile, you may have a try sending the ICS file as a separate attachment rather than embedding it in the email body.

    I look forward to your response.

    Please note that our initial response may not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.

    Thanks for your precious time and your understanding would be highly appreciated. Have a nice day!Best regards,Allen | Community Moderator

    0 comments