Assume that a meeting request that has table content, embedded images, and attachments is created in Microsoft Outlook 2016. Then, you receive the meeting request in Outlook 2013. In this situation, the tables, images, and attachments are missing or corrupted in the received meeting request.


To fix this issue, install the December 6, 2016, update for Outlook 2013 (KB3127975), and then follow the steps to enable the functionality to allow the display of HTML calendar items, meeting requests, and other calendaring content for compatibility with Office 16 HTML calendaring.

Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.

  1. Exit all Microsoft Office applications.

  2. Start Registry Editor:

    • In Windows 10, go to Start, enter regedit in the Search Windows box, and then select regedit.exe in the search results.

    • In Windows 8 or Windows 8.1, move your mouse to the upper-right corner, select Search, type regedit in the search text box, and then select regedit.exe in the search results.

    • In Windows 7 or Windows Vista, go to Start, type regedit in the Search programs and files text box, and then select regedit.exe in the search results.

  3. Locate and then select the following registry subkey:


  4. On the Edit menu, point to New, and then select DWORD Value.

  5. Type AllowHTMLCalendarContent, and then press Enter.

  6. In the Details pane, press and hold (or right-click) AllowHTMLCalendarContent, and then select Modify.

  7. In the Value data box, type 1, and then select OK.

    Note This functionality is OFF by default. This functionality does not allow composing HTML calendar content. If you set the value of the registry key to 0, the functionality is disabled. If you set the value to 1, the HTML calendar content is displayed correctly.

  8. Exit Registry Editor.

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