Migrating between Office 365 tenants; what we learned
Posted on 13 November 2018 by Beaming SupportBefore you get too far into this guide, please heed our advice against migrating from Office 365 to Office 365 tenant. Microsoft does not provide any help in moving between the Office tenants. Why? We can only speculate.
If you do have to complete this task, then hopefully the steps below, learned from our experience of migrating between Office 365 tenants, will assist you.
The Export Process
If you have used the Office 365 eDiscovery method of exporting emails, then you will be familiar with the nice little PST package that is exported as your emails, calendars and contacts.
This is no more, as the export process has Inbox, Drafts, Deleted items etc, but they are all empty. Instead you are given a folder called ‘Primary Mailbox’ which contains all of your emails, calendars and contacts. This will cause havoc if you try to import it straight into your new empty mailbox, as the main folders will remain empty. You will still have your entire mailbox in the form of a ‘Primary Mailbox’ folder. This means that your calendar and contacts will appear empty, but will both have sub folders called Calendar and Contacts respectively. These folders will contain all of your data, effectively giving you two calendars and contact lists. These will also cause issues for mobile and tablet users.
The Correct Export Process
There is only one method that seems to work correctly, but it is time consuming. You will have to create an account that has email access on the old platform, for example migration@domain.com. Then create an Outlook profile using this account and grant the account full access to any email accounts that need migrating.
This is where the process is time consuming: Open Outlook and let the email accounts fully sync with Office 365. We suggest 2 mailboxes at a time max. Make sure that your migration account is set to ‘All’ under emails to download (account settings, highlight migration account and change), as this will filter down to the user accounts.
Once that is complete, use the Outlook menu and go to File, Open & Export, Import/Export.
Choose ‘Export to a file’, .pst, then select the name of the user to export. Make sure “include subfolders” is ticked and press Next. Choose a location for the PST and the duplicate options, then Finish. Next choose a password if you wish and then wait.
The Import Process
The easiest way of importing into Office 365 is to use the PST Import tool.
Load up the Office 365 admin page and open the Setup tab. Select ‘Data Migration’, then ‘upload PST’.
Create a new import job and give it a name (be aware no upper case letters are allowed). Select Next, then show the ‘Upload SAS URL’. Make a note of this URL for use later and download the Azure AzCopy tool.
Now you will upload the PST files to Office 365. Open a command prompt in the location you exported the upload tool to (default C:Program Files (x86)Microsoft SDKsAzureAzCopy) and type the following:
AzCopy.exe /Source:<Location of PST files> /Dest:<SAS URL> /V:<Log file location> /Y
This script needs a bit of formatting to make sure it works properly.
| Source | This is easier on the local system, so /source:”D:PST” for example. Note that this will upload all files in this directory. |
| Destination | Enter the SAS URL that you made a note of earlier. /Dest:”112233445566778899” |
| Logging | This is where the verbose logs will go, /V:”D:pstlogs” for example. |
| Optional | /S will copy files in subfolders as well as the root folder. The files will upload to the same subfolder within Office 365 (more on this later). |
Now we need to prepare the mapping file, so open Excel and make the following column headings:
Workload, FilePath, Name, Mailbox, IsArchive, TargetRootFolder, SPFileContainer, SPManifestContainer, SPSiteUrl
The file should look like the below image.
The headings mean the following:
| Workload | This will be exchange, as they are PSTs. |
| FilePath | This is the path you uploaded the files to in the previous step. A dot is the root directory, where as a /folder is the name of the subfolder you used. |
| Name | This is the name of the PST file you wish to use, that has been uploaded. |
| Mailbox | This is the email address of the user where the emails should be uploaded to. |
| IsArchive | False if this is a mailbox, true for adding as an archive. |
| TargetRoot | This specifies where the emails should go, either Inbox to Inbox, Sent to Sent etc or if the entire previous mailbox should be dumped in to a subfolder in the new mailbox. |
SPFileContainer, SPManifestContainer and SPSiteUrl should be commas as the example shows.
Once this is underway, we can go to the next step. Tick both ‘I’m done uploading my files’ and ‘I have access to the mapping file’, then Next.
Select your mapping file and click validate. The file will now be checked for validation and let you know if there are any issues. If the validation is green, you can click save. Office 365 will now run through some things in the background and give you a success message when complete.
Hit close twice and then periodically hit refresh until the progress says ‘Ready to import to Office 365’.
Once you have this status, click it to start the import process. This will open a popup that will let you know the level of analysis and give you the option of importing the emails. Click Import to Office 365, decide if you want to filter any data, then click Import Data.
Depending on the mailbox size, this process will take some time. Click Close to view the progress of the import.
Once the import has finished your new mailbox should start syncing and you’ve completed the process of migrating between Office 365 tenants.
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