How to migrate or synchronize Exchange mailboxes between different Office 365 accounts
See here how to get your date synchronized or copied into different Office 365 accounts.
1.) You need ExMixedFolders from this location.
2.) After the installation is ready, the configurator-program will start.
3.) Please create in the upper window one new connection to the first Office 365 account ( For easy connection, please use the autodiscover option )
4.) Now you can create another connection to your second account like in step 3.
5.) In the bottom window you can now create a new synchronizationtask. Please choose the account 1 on the left side. Use the folder-dialog to select the mailbox root of this account.
6.) Use the arrow right in the choicebox.
7.) Select the second account on the right side and the mailbox-root as well.
8.) Also select the "synchronize subfolders" option.
9.) After you select Service => restart service, the process will start.
10.) You can watch the process in the configurator or on the Service => logging => folderoverview.
11.) After everything is ready, you can now uninstall the program if you don't want to synchronize still in background.