Hi all,
a customer of us did export a Calendar of a MAC user from his Exchange 2010 Mailbox and import it to his Exchange Online Mailbox. Ex- and Import was done by a Windows Client and Outlook 2010. The Mac User opened his Exchange Online Mailbox by Outlook for Mac and got only for imported Calendar Entries error code -19126. By Details of this error there is following messsage: Delete this Entry and create a new one. Well, this is an option but there are round about 600 imported Calendar Entries!