Tools to mass export O365 mailboxes to PST files


Will appreciate your help with the following task. The company where I work (company A) has acquired a company (company B) that has all its mailboxes hosted in O365. At the time of acquisition, the users of company B were issued a company A mailbox. As a result, currently those users have two mailboxes, one for company A another for company B. Our goal is to eliminate the user’s O365 mailboxes and end up only with company A mailbox. Our plan is the following:
-Configure company B users Outlook application to connect to company A mailbox
-Export O365 mailbox to PST file
-Import PST file content to Company A mailbox
The problem with this plan is that O365 doesn't offer a native and efficient way to perform multiple exports of mailboxes to PST files. I am currently evaluating an export of a mailboxes using "MessageOps Exchange Migrator" application but this solution only exports a mailbox at a time and it has been running 3 hours to export a 5GB mailbox. The average size of company B mailboxes is 5GB therefore I would like to find a better solution even if it is a paid solution (software or solution vendor doing the work for us) so that the exports of 380 mailboxes can be performed over a weekend (Friday evening, Saturday and Sunday). Hope somebody in this forum can provide a better approach or paid software solution to achieve this goal.

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VB ITSSpecialist ConsultantCommented:
For any sort of mass mailbox migrations I always recommend MigrationWiz. I've had nothing but great experiences with it. You can check it out here:

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Hello WorldCommented:

We can use Import-Mailbox and Export-Mailbox to import and export PST file to mailbox in Exchange 2007, for your reference:

It's support in Office 365, however we can use PST Capture to import PST file. Please refer to:
Mark GalvinManaging Director / Principal ConsultantCommented:
I use MessageOps Exchange Migrator for going from Office 365. very good.
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doloresmjAuthor Commented:
Thank you for your input Ya Li. Unfortunately in O365 there is no export option in PowerShell (New-MailboxExportRequest) and the only portal option to export to PST is using eDiscovery which is a non-acceptable slow solution for my situation.

Mark Galvin, thank you for mentioning this neat tool (MessageOps), I have ran a test and it can only process one mailbox at a time, it took 4 hours to export 5GB mailbox. We have 300+ mailboxes with average size 5GB to migrate over a weekend so it is not a desirable solution. In theory I could install the application in multiple systems, which will require multiple o365 admins accounts to work around user throttling policies but it would be an awkward solution. Nice tool to do a few export for archival purposes.
doloresmjAuthor Commented:
VB ITs thank you for the suggestion. I will check the tool MigrationWiz to find out if it can be a good tool for our migration needs. At this point I am not awarding points (will do in a couple of days) but seems that your might be the most appropriate solution. Thank you all for providing ideas.
doloresmjAuthor Commented:
Thank you all for your information. I am currently evaluating migrationWiz and seems to be the tool to use however I am still struggling to obtain the following objective: Migrate all the O365 folder structure to single folder to destination Exchange 2010 mailbox and keep the folder structure within that destination folder. This far I have obtained the following results : all types of email objects get dumped on destination folder or multiple folders get created outside inbox structure. I have used the following folder mapping options and so far no luck.  

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