It can be a challenge to import PST files to Office 365. With PST Migrator from LAE Software, the challenges with PST files can be mitigated. Let's take a look at the difficulties with PST files and how LAE's PST Migrator helps to solve them.

What are PST files for?

The personal storage table (PST) file format is a proprietary message file format specific to Microsoft technologies. It allows storing copies of messages from Microsoft email solutions, such as Exchange Server and others. It grew in popularity years ago as it offered a way to both archive copies of emails and provide local copies, as opposed to storing them on the email server.

As mailbox quotas were introduced and enforced, PST files were often used to provide access to large amounts of emails without the restrictions imposed by a server quota at the mailbox level. Additionally, back in legacy versions of Exchange Server, administrators used PST files as a way to archive copies of mailboxes.

Why aren't PST files needed with Office 365?

Space is no longer a limiting factor with respect to the email storage provided in cloud email solutions, such as Office 365. The storage offered is usually sufficient for any general-purpose email the user works with; in addition, the storage space is large enough to store the contents of the user's PST files. When more space is needed for a particular user, the storage is easily expandable with a few clicks in most cloud environments. So, as you can see, space is no longer an issue regarding the use of PST files.

PST files are very prone to corruption, which can lead to increased support requests and even data loss. Additional challenges can result from compliance regulations. And simply being able to keep up with the location of all email data for a particular user is a challenge in itself. PST files can be created and utilized with no real structure or planning for their use. This can lead to PST files being created all over the network, which makes it difficult to have the visibility needed for proper management.

What are the native Office 365 PST migration options?

Microsoft offers the following methods to migrate your PST data to the Office 365 cloud:

  • Network upload to the cloud – Microsoft allows you to upload copies of your PST files to what it calls "temporary" Azure storage. Then you use the Office 365 Import service to import the data from the uploaded PSTs to the specific user mailboxes.
  • Drive shipping – You can BitLocker-encrypt a portable hard drive, copy your PST files there, and then ship the drive to Microsoft. They will copy over the data from the BitLocker-encrypted drive to a temporary Azure storage location. You will then be able to use the Office 365 Import service to import the PST data into the desired mailbox locations.

The methods supported natively by Microsoft are cumbersome to say the least, requiring you to first upload your PST files to an Azure location or send in a drive containing your files and have these copied to Azure for you.

How can LAE Software's PST Migrator simplify PST import?

The PST Migrator tool from LAE Software is an automated PST file migration utility that enables easily migrating email contained in on-premises PST files to your Office 365 cloud email service.

PST Migrator is a self-contained executable that does not require an installation, making it very portable. Aside from its ability to run in a "sneaker net" fashion, running the program ad-hoc, PST Migrator can be deployed effectively in larger environments with many users using the following methods:

  • GPO object
  • Other tools, such as LANDesk, Microsoft's SCCM, and LabTech

As noted in the deployment details, the PST Migrator tool can be run ad-hoc either by running the executable or by some automated means, such as deployment through group policy. Running the tool on a single machine under your logged-in user helps you to get an idea of what PST Migrator can do.

In the screenshot below, you see there is a PST file mounted in Outlook. The Outlook profile is connected to an Office 365 Exchange mailbox. When the PST Migrator for Outlook.exe file is executed, the process begins migrating data between the mounted PST file and the Office 365 inbox.

Files contained in the PST Migrator for Outlook ZIP package

Files contained in the PST Migrator for Outlook ZIP package

When PST Migrator is executed, the tool creates a folder structure based on your configuration in either the mailbox or the online archive. It then recreates the folder structure found in the PST underneath. Email items are migrated in real-time between the PST file and your Office 365 inbox. You will see messages leaving the PST file if you monitor the items it contains.

One of the nice features of PST Migrator is item-level migration. This helps to fight the corruption that can often creep into PST files. PST Migrator migrates email on an email-by-email basis, according to what it finds in the PST file. Even if there is corruption that affects a few email items, it will not prevent migrating other email items from the PST file that are not affected by the corruption.

Running the PST Migrator tool to migrate email from PST files to your Office 365 inbox

Running the PST Migrator tool to migrate email from PST files to your Office 365 inbox

Once the migration of emails from the PST file is complete, you will see a "Completed" message. The PST file is also disconnected from Outlook once the session is complete.

A successful migration of email items from a PST file to your Office 365 mailbox

A successful migration of email items from a PST file to your Office 365 mailbox


If you are planning a migration to Office 365 for your organization's email, managing and migrating PST files can present a tremendous challenge. However, PST Migrator provides a really easy way to migrate the data contained in PST files to your Office 365 environment.

It works well with automated deployments by means of group policy and other tools. The migration itself happens in real-time during the logged-in user's session. It also notifies the user when the process is complete and cleans up the connection to the legacy PST file.

While there are a couple of native PST migration capabilities found in Office 365, PST Migrator provides an easy, single-step approach to migrating your data, unlike the need to first copy your PST file data to Azure and then perform the import.

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Check out a YouTube demo of the PST Migrator software below [insert video] and download a copy of the LAE Software PST Migrator software.

  1. Leos Marek (Rank 4) 4 years ago

    Hmm how worthy is to transfer gigabytes of old emails in PST files, where the search ratio is like 1 search per year in 80-90% of cases? 

    • Bob Larkin 1 year ago

      It’s not a question of how worthy it is. It’s a question of what is going to happen.
      And this IS going to happen. I read up on how the tool works and it will find and copy every email in every pst the end users have regardless of where it resides, with the exception of copies of pst files with the same contents.
      Many of these end users also have legal obligations to retain emails for extensive amounts of time. So, like I said, this is going to happen. So how is performance affected when it is moving the contents of say a 20 gb pst file to the archive? And if it’s local, how long would that take? And if they still (many do) have their pst’s on network drives and are on vpn. how will that affect performance?

  2. Bob Larkin 1 year ago

    I am in IT at a global IT company working in an enterprise environment. While the video was educational, I don’t see how Outlook performance will not be degraded if the pst migrator tool is moving literally 10’s of gigabytes of data, often over a vpn connection to a network drive.
    Even if the files are all local, I have personally seen pst files in the 60 gb and higher range or a number of them totaling that much space. How is moving that much data not going to impact Outlook performance and what measures can be implemented in the event this occurs? I saw the configuration guide but at my level, I won’t have access to that. I’m fairly certain they are deploying via gpo. What kinds of issues HAVE you seen with this software?

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