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Migrating offline Outlook files from Mac OS X to Office 365

18 May 2016 by Thomas Madsen

New software streamlines discovery and eradication of Outlook for Mac data files
We recently looked at the great new features of PST FlightDeck – including its deep integration with Microsoft Azure and Microsoft SQL Database. One of the most significant developments is its support for migrating offline Outlook for Mac files.

Organizations are increasingly migrating their corporate email ecosystems to Office 365 for improved security, compliance and manageability. But one of the major hurdles in such projects is the discovery, repair, migration and elimination of offline files – those with a PST extension in a Windows environment.

PST FlightDeck is a mature and highly-sophisticated solution that has successfully migrated millions of PST files from desktops, notebooks, removable drives and shared disks over the years. Now, with the release of PST FlightDeck 5.0, that same functionality and ease-of-use is at last available for corporate Mac deployments.[vc_column width=”1/4″][vc_column width=”3/4″]About Outlook for Mac (OLM) files
Our local resident Mac expert Wayne Humphrey says “until now the only practical method of migrating offline Outlook for Mac data files – carrying the OLM file extension – has been to export/convert or manually archive the items prior to migration. Not only is this a time-consuming and somewhat awkward business, but it relies on individual users to carry out the work; there has been no way to centrally manage the process and to ensure no rogue OLMs remain at large”.

PST FlightDeck 5.0 essentially manages OLMs in the same way it handles PST files, ensuring that any device running OS X (rumored to be renamed macOS very soon) can be included in a corporate sweep of devices in the same way that Windows offline files can be centralized and eradicated.

Better control, compliance and security for Outlook on Macs
The increasing maturity and stability of Office 365, along with its clear cost model, has led many enterprises to migrate live email and archives into the service. But migration projects also need to take into account offline files that have been generated on other remote devices. These files can contain vital information for legal defense for example, and are susceptible to leakage (as in the 2014 Sony hack, when thousands of confidential emails were obtained).

Any organization that has been running Microsoft Exchange Server will have been generating offline files. PST FlightDeck is a proven solution that has been used by hundreds of public and private sector enterprises worldwide to eliminate PSTs from Windows environments.

A similar problem, affecting Mac environments, is becoming more urgent for two reasons. Firstly, individuals are pressing IT departments to support their OS X devices. The use of these devices is on the increase because employees and contractors often prefer Macbooks for performance and other capabilities. Secondly, Microsoft has thrown its full weight behind Macs as part of its strategic vision for Office 365. Rob Howard, Microsoft’s director of the Office 365 ecosystem, recently confirmed that “support for Office 2016 for Mac is a big step for us.”

Why legacy and archive Mac files pose the main risk
The offline file problem does not really affect new email accounts connected with Office 365. But any existing employee who has moved from PC to Mac – even recently – could well have created local offline files. Users typically convert PSTs to OLMs so that they can retain access to them two or three years down the line from when they were created. Just like PC-based PSTs they’re subject to the same vulnerabilities.

The corporate objective is to bring these files back under central data control. In practice that means locating, identifying, centralizing, de-duplicating and repairing, migrating and finally eliminating the original file at source. Users retain access to the data direct from Office 365 rather than a local file.

PST FlightDeck is the first and only solution on the market for OS X that automates the migration and eradication process from end to end. Used strategically as part of your Office 365 migration PST FlightDeck will help you take back control, demonstrate compliance, and improve security throughout the enterprise. And QUADROtech remains the only migration vendor with a single suite of proven solutions for migrating essential live mail and archives as well as offline files.


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Enterprises that have used Microsoft Exchange Client or Outlook typically have many thousands of PSTs and OLMs scattered throughout the infrastructure, on desktops, notebooks, removable disks and shared network drives. Getting rid of them is high on the agenda for compliance officers as much as IT specialists.

Offline files pose a major security risk: The portability of PSTs and OLMs exposes organizations to data leakage. Offline files are susceptible to malware and encryption and password protection are easily circumvented by attackers.

Offline files are a legal and compliance obstacle: Organizations cannot enforce retention policies, and legal departments struggle to ensure they have the right data to defend cases.

Offline files inhibit business-aligned change: PSTs and OLMs are a blocker to modern client architectures involving multiple devices, VDI and BYOD.

Offline files are inefficient and not centrally manageable: Attempting to centralize PSTs and OLMs risks data loss, file corruption and Outlook speed reduction. Organizations do not know how many offline files exist in the infrastructure, where they are, or whether they are corrupted.
For a more detailed look at the subject – independently edited and with a foreword by Tony Redmond, senior contributing editor for – download a copy of The Complete Guide to Eradicating PST Files at Amazon: