Why does Gmail Not Open an OST File?
An OST file is an offline copy of one mailbox in one Outlook profile. Gmail has no command that reads the format.
You move the mail through Outlook, through a PST file or with a converter. The route depends on whether Outlook still opens the OST file.
| Situation | Route | Cost |
|---|---|---|
| Outlook opens it | IMAP drag and drop | Free |
| Outlook opens it | PST export and Google migration | Free |
| Orphan or damaged copy | OST Converter | Paid |
How do You Move OST Mail to Gmail With IMAP?
Gmail stores the mail on Google servers, so the mail counts against your Google storage. Read the guide to the Gmail storage limit before a large upload.
A big mailbox takes hours to upload. Close no window until the sync ends.
Can You Export the OST to PST and Import the PST?
Method #2: PST Export and Google Migration (Free)
Use it when. You use a Google Workspace account. Extra application. Google migration software.
- In Outlook, select File, then Open & Export, then Import/Export.
- Choose Export to a file and Outlook Data File (.pst).
- Select the mailbox and save the PST file.
- Install Google Workspace Migration for Microsoft Outlook and sign in to your Google account.
- Choose the PST file and select Migrate.
Google describes the tool on its page for moving Outlook content to Google Workspace. The tool imports mail, calendar events and contacts from an Outlook account or a PST file.
The tool targets Google Workspace accounts. Use Method #1 for a personal Gmail account.
What can You do With an Orphan Mailbox Copy?
Method #3: SysTools OST Converter (Paid)
Who it suits. Users with an orphan, damaged or inaccessible OST file. Extra application. Windows PC.
SysTools OST Converter reads an OST file directly and exports to PST and other formats. The software needs no Exchange connection and no Outlook profile.
- Start OST Converter and add the OST file.
- Preview the folders and select Export.
- Choose PST and select a destination folder.
- Import the PST file into Gmail with Method #2 or Method #1.
The free demo exports 25 items per folder.
Read the guide to convert OST to PST for the full steps.
What are the Limits of These Methods?
- Method #1 needs an OST file that Outlook still opens.
- A damaged copy needs a converter first.
- Gmail storage fills with the uploaded mail.
- Google migration software targets Google Workspace accounts.
- A converter demo exports 25 items per folder.
Heads Up. Count the messages in one folder before and after the upload. Retain the OST file until the counts match.
Where Else do You Go From Here?
- Check the OST format with the OST file extension page.
- Save OST mail as PDF with the guide to export OST to PDF.
- Move mail the other way with the guide to import Gmail to PST without Outlook.
Frequently Asked Questions
Can Gmail Open an OST File?
No. Gmail cannot read the OST format. Move the mail through Outlook or a converter.
How do You Import OST to Gmail for Free?
Add your Gmail account to Outlook with IMAP and drag the OST folders into it.
Can Google Migration Software Import an OST File?
The tool imports from an Outlook account or a PST file. Export the OST mailbox to PST first.
Does the Google Tool Work With a Personal Gmail Account?
The tool targets Google Workspace accounts. Use IMAP for a personal account.
How do You Import a Damaged OST Copy to Gmail?
Convert the OST file to PST with a converter and import the PST file.
Does OST Converter Need Outlook?
No. The vendor states that the software needs no Exchange connection.
Does the Demo Import Every Email?
No. The demo exports 25 items per folder.
Author's Verdict
Use IMAP when Outlook still opens the mailbox and a converter when it does not.
Count the mail in Gmail before you delete the OST file.
Key Takeaways
- Gmail cannot read an OST file.
- IMAP moves OST mail through Outlook.
- A converter handles an orphan OST file.
Related Guides