PST to Microsoft 365 Migration Guide

If your company still has old Outlook data files (PSTs) scattered across random computers and servers, you are definitely not the only one. Even though it is 2026, these digital leftovers are everywhere.
These files were once helpful for saving space, but they are now a huge risk. They are easy to lose, hard to back up and a nightmare for security. Thus, most businesses now move these files into Microsoft Office 365. There are certain methods to import PST to Office 365 which you can see below.

How to Migrate PST Files to Microsoft Office 365?

Below given is the modern and updated way tomigrate PST to Office 365.

Step 1: Identify and Locate PST Files

You would be surprised how many old files are tucked away in corners of your network.

• Where to look:Employee laptops, shared office folders, plug-in hard drives and old backup tapes.
• The Smart Way: Do not hunt for them one by one. Use discovery tools (like Microsoft’s own scripts) to scan your network automatically. It saves days of manual work.

Step 2: Choose Your Migration Method

1. The Official Microsoft Way (Best for most): You upload your files to a secure digital “loading dock” (Azure Storage), and Microsoft moves them into the right mailboxes. It is free, safe, and handles large amounts of data well.
2. The Manual Way (Only for 1-2 people): An employee manually drags and drops the file into Outlook. This is slow, prone to mistakes and hard for IT to track. Avoid this for teams.
3. The Third-Party Migration Tools (Best for Big Companies): If you have thousands of files, use paid tools like Goldytools Import PST to Office 365. They are faster, give better reports, and let you schedule the migration for after-hours.

Step 3: Prepare Microsoft 365 for PST Import

Before you start the migration, make sure the space is ready for the files:

• Create the user accounts and give them licenses.
• Set up Archive Mailboxes. If a file is huge (over 40GB), it is better to put it in an archive folder so that it does not slow down the user’s main inbox.

Step 4: Upload PST Files

• Upload the files to the secure storage area.
• Tell the system which file belongs to which person.
• Start the job and watch the progress on your dashboard. Microsoft does the heavy lifting while you just monitor.

Step 5: Validate the Data

Once the move says Finished, don’t just take its word for it. Check a few mailboxes to ensure:

• The folders look right.
• Attachments and calendar invites are all there.
• Pro Tip: Ask a few key users to look through their Legacy Folder to make sure their most important old emails made the trip.

Step 6: Archive or Delete Old PST Files

• Delete the old files:

  Remove the PSTs from laptops and servers so they do not take up space or get stolen.

• Lock it down: Change your settings so that employees cannot create new PST files in the future. This keeps everything in the cloud where it belongs.

Conclusion

There might be various methods to migrate PST files to office. But, it is always better to use third party tools like Goldytools for faster and better results. You can use the free version of Goldytools import PST to Office 365 free.