Email Migration Tool for Gmail and Office 365 uploads mail from PST, MBOX and EML files into a live mailbox. The folder tree and the original dates are kept, and a second run skips what is already there.
Microsoft and Google offer free mail import methods.
Download the Email Migration Tool and install it. Click Add files and pick your PST, MBOX or EML files. Add folder takes a folder of EML files with its subfolders. The program reads your files without changing them.
Pick your destination under Email service. For Gmail, enter your address, fill in App password and click Connect. For Microsoft, enter your address, click Sign in with Microsoft and enter your password on Microsoft's page. Wait for Connected.
Tick folders on the left under Folders to migrate. The right side shows their destinations, with new folders marked will be created. Leave Destination folder unchanged to import into Imported, with one subfolder per file.
Click Start migration. The screen counts Moved, Already in the mailbox and Errors as it runs. At Migration complete, click Open migration log for the report.
Manual imports often stamp email with the import date. Email Migration Tool for Gmail and Office 365 keeps the original date: your invoice from 2019 still sorts under 2019. We checked on a live Gmail mailbox. Dates matched to the second.
If your connection drops, the program reconnects automatically, with up to 5 attempts in a row and waits from 2 to 30 seconds. You get an estimated duration before you start. We do not promise a speed.
The program reads your disk and connects directly to Gmail or Office 365, without passing through our servers. We do not save passwords. The Microsoft token stays in memory, so you sign in with Microsoft again at the next launch.
Email Migration Tool for Gmail and Office 365 checks the first bytes, ignoring the extension. A Thunderbird file without an extension is treated as MBOX. You can add several files at once.
Choose Gmail, Microsoft 365 / Outlook.com, Yahoo Mail, iCloud Mail or Other IMAP server. For your own server, fill in IMAP server, Port and Security. Defaults are port 993 and SSL/TLS; STARTTLS is also available.
A journal records each delivered email. If you shut the lid or cut the power, your next run picks up where it stopped. We deliberately killed the process 4 times during a 130-email run on our own test IMAP server. Extra copies? Zero.
Deleted Items, Junk Email, Trash and Spam start unticked. Use Period to select the last 12 months or your own range. Nested folders are recreated parent first. Tick Merge into the mailbox folders to map Sent Items to the mailbox's Sent folder.
The final screen lists Moved, Already there and any Errors per folder. Open migration log opens a text report with columns per folder, including existed and too big. Messages over the server's size limit are skipped with the reason recorded. A damaged PST does not block other files.
Choose from 20 languages in the Language menu, including German and Japanese. The program runs on 64-bit Windows 10 and 11 with ordinary user rights. You do not need to install .NET.
Years of email in one PST on your old computer, a browser on the new one. Copy the PST across and import it once.
Your provider or employer has set a date to close your address. Export your mail while you can; import it into your own Gmail later.
A former teammate's correspondence arrives in one huge PST. Import the two folders you need and leave the rest in place.
Before your student login expires, get your mail as an MBOX from Takeout. Webmail cannot use that file directly. Import it into personal Gmail to search it like your other mail.
You check email on the web now. Bring your decade of Outlook history into Gmail and search it alongside this week's messages.
You manage a handful of Microsoft 365 mailboxes, with a PST for each employee from the previous setup. At each desk, sign that person in and import their PST. If Office 365 asks for IT approval, that falls to you.
Gmail will not accept your Thunderbird profile or Takeout archive directly. Import that mail with the program without setting up a desktop client.
File sources and what reaches your mailbox.
Mail service rules apply to your import.
Gmail accepts about 500 MB a day over IMAP. The program counts today's uploads and pauses before the limit, resuming automatically after midnight if you leave its window open. If you close it, press Resume next time, add the same PST and reconnect. A 10 GB PST takes about 20 days.
Gmail requires an app password instead of your regular password; this version has no Google sign-in button. Create an app password in your Google settings with 2-Step Verification enabled. Google may not offer app passwords for work, school or other organization accounts. This version cannot connect to those accounts without one.
By default, your import goes under Imported plus the PST name, a Gmail label, with nothing added to your Inbox. Switch on Merge to put the PST's Inbox into your Inbox. Deleting the label leaves the messages in All Mail.
Sign in with Microsoft opens Microsoft's page in your browser. The program never sees your password. The consent screen shows Outlook Mail Merge, our registration for this sign-in.
Your work or school tenant may require administrator approval, and IMAP must be allowed. What to show them names the permission; Copy for the administrator copies the wording. Test sign-in with the free trial before planning a big move.
Use a PST; the program cannot read OST or a live Outlook profile. In Outlook, export your mail through File, Open & Export, Import/Export, Outlook Data File (.pst). Quit Outlook before the run because it locks the PST.
A PST does not store messages as they arrived. The program rebuilds each one from its subject, sender, recipients, date, plain and HTML body, and attachments, so the result is not a byte for byte duplicate. MBOX and EML go in unchanged.
The trial runs every feature and never expires. It is limited by the number of messages.
Trial uploads are real and stay in your mailbox. After you enter a key, click Move the rest and the program skips them.