Running Outlook 2013 on Windows 8.1 Virtual Machine on a Mac


Does anyone know how to resolve this recurring error message from Outlook 2013 running on a Windows 8.1 Virtual Machine (using Parallels on a Mac).

Each time a Calendar item is edited or accessed, Outlook generates the following message. "The form region "Apple.DAV.Appointment" cannot be opened. The form region manifest contains invalid XML."

The only option available is to click OK, until it recurs.

See snipet:

Would appreciate any help!!

Thanks in advance.


Hello Greogory,


Do you have any icloud add-in installed for Outlook 2013?


Open Outlook in its application safe mode then try access or edit calendar item and check how it works.


Click Start > start typing 'outlook /safe' (Without the quotes and note the space in the command)



If you’re able to work with Outlook in safe mode, then follow the steps below to disable add-ins.

A.    Click File menu, click Options > Add-in, click Go button in the Manage: Com-in Add.

B.    Check if there is any add-in; clear the checkbox to disable it.


You may also refer to the thread link mentioned below which discusses the similar and issue:


Let us know the result to assist you further.

Thank you.

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Question Info

Last updated November 10, 2020 Views 6,880 Applies to: