Why are PST files too large to email?
A short message fits in an email. Years of mailbox content do not. Contracts, photos, and PDFs can make the file several GB, sometimes tens of GB. Gmail does not accept attachments over 25 MB, and Outlook does not accept attachments over about 20 MB.
Attaching an archive to a new message means trying to fit an entire mailbox into one email. A link is not an attachment. The file is not embedded in the message. There is no add-on. The recipient downloads from the link and imports the archive into their own email program.
SendGB does not compose a new email. It transfers a copy of an existing mailbox.
| Method | What happens | Suitable for a mailbox? |
|---|---|---|
| Gmail or Outlook attachment | Attachments over 20–25 MB cannot be sent | No |
| Forwarding messages one by one | Years of mailbox content get scattered | No |
| Shared drive | Requires an account and ongoing access | Use with care |
| Connecting to a mail server through us | We don’t access your mailbox | Not available |
| SendGB link | The archive is not opened or sent as an attachment | Suitable for delivery |
The example above is a transfer within the free limit: an Outlook archive, an MBOX folder, a contract stored outside the archive, a folder list, and a short note. A complete mailbox built up over years will be larger than this example.
Opening a mailbox vs. sending the file
Opening a mailbox means importing its messages into an email program. The recipient’s Outlook or Thunderbird does that. We don’t. We don’t convert PST to MBOX or MBOX to PST.
PST is Outlook’s archive file that you can share with someone else. OST is the same program’s working copy. It may be locked while Outlook is open. Close the program and export a clean copy as PST yourself. We don’t convert OST or repair damaged files.
MBOX is a file format used by Thunderbird and Apple Mail to store an email folder. Include the name of the program it came from in your note. We don’t open the program.
| Individual messages | Single archive file | |
|---|---|---|
| Purpose | Selecting a few messages | Sharing years of mailbox content |
| File | A separate EML for each message | PST or MBOX |
| Count | Stops at 500, or 2,500 with SendGB Extra | Usually one or a few files |
| Reading | You read the messages | We don’t open it |
| What we do | We don’t merge files | We don’t change the format |
EML is a single message. It works for a handful of selected messages, not for an entire mailbox. Tens of thousands of files exceed the limit.
What should you include with the archive?
The archive may be a single file. Without a description of what each folder contains, the recipient may open the wrong year.
| File | What it provides | Without it |
|---|---|---|
| PST or MBOX | The mailbox itself | There is no archive to import |
| Folder list | The year and account | The wrong mailbox gets opened |
| Short note | The program and date | The recipient may expect a PST but receive an OST |
| Exported attachment | A separately saved contract | We won’t extract it from the archive |
| Password note | The file’s own password | It won’t open unless the password is shared through a separate channel |
We don’t extract attachments from the mailbox. If you include the contract separately, that PDF may be displayed on the download page. PST and MBOX files do not open. Folder names remain intact when the entire transfer is downloaded. See the guide to sending folders for details. If you have zipped the archive yourself, it is sent without being opened, as described in the guide to sending ZIP files.
This file contains other people’s messages, identity documents, and contracts. Protect the link with a password. Send the password separately from the link. The PST file’s own password is a separate lock. Don’t confuse the two. We don’t remove content from the archive. To send a single PDF separately, see the guide to sending PDF files.
Is 5 GB enough for a mailbox?
A year of simple correspondence may fit within 5 GB. Years of messages with attachments will not. Free transfers stop at 5 GB and 500 files. For a single PST, size is the limit. If each message is a separate file, file count is the limit.
Plain-text correspondence may shrink when compressed. An archive full of photos and PDFs will not shrink much when zipped again. You handle the compression. We don’t open or recompress the archive.
| What are you sending? | In practice | Which option is enough? |
|---|---|---|
| A small folder | Under 5 GB | Free; up to 90 days for files up to 250 MB, 7 days above that |
| A PST covering several years | Often close to or over 5 GB | Free if it fits; SendGB Extra if it exceeds the limit |
| Each message as a separate EML | Tens of thousands of files | Hits the 500- or 2,500-file limit; create a single archive |
| A complete mailbox with attachments | May be tens of GB | SendGB Extra, 500 GB per transfer |
| A single archive over 500 GB | Rare | SendGB Exceed, up to 1 TB |
SendGB Extra starts at €29.90 per year. It includes 1 TB of storage. SendGB Extra keeps files for up to 1 year. The limit per transfer is 500 GB and 2,500 files. It suits people who frequently export large mailboxes.
SendGB Exceed does not require a membership. A 1 TB transfer costs €9.99. The code can be used once and is valid for 1 year. The link stays available for 7 days. The file count limit is 2,500. It is enough for an occasional single archive over 500 GB. We cannot send more than 1 TB in one transfer.
Don’t make this link your company’s only archive. Free transfers over 250 MB stay available for 7 days. Free transfers up to 250 MB stay available for up to 90 days. SendGB Extra keeps files for up to 1 year. You keep the original copy. We don’t manage legally required retention periods.
If you entered your email address, you receive one notification when downloading starts. With email delivery, you are notified once per recipient. With link delivery, you are notified once per transfer. If the same person downloads again, no new email is sent. The notification does not confirm that the entire archive has downloaded or been imported into an email program.
How to send
- 1
Add the archive
Add your exported PST or MBOX file to the upload box. You can include a folder list and a short note in the same transfer. The free limit is 5 GB total and 500 files. If you exceed either limit, you need SendGB Extra or SendGB Exceed.
- 2
Send the link
Email the link to the recipient or copy and paste it into a message. Add a password if the archive includes someone else’s messages. Send the password separately from the link. If you enter your email address, you receive one notification when downloading starts.
- 3
The recipient downloads
The recipient downloads from the link and does not create an account. The archive does not open on the download page. The recipient imports the file into Outlook or another email program they use. Free transfers over 250 MB stay available for 7 days. Free transfers up to 250 MB stay available for up to 90 days. SendGB Extra keeps files for up to 1 year.
What happens to your file?
- We leave the file untouched. The archive is not opened, messages are not read, and the format is not changed.
- PST, OST, and MBOX files download as they are.
- The accompanying list and note go in the same transfer.
- If you entered your email address, you receive one notification when someone starts downloading.
What we don’t do
- We don’t connect to your mailbox. You export and import the archive yourself.
- We don’t convert OST to PST or repair damaged archives. There is no add-on.
- If you send messages as individual files, the free limit is 500 files. SendGB Extra and SendGB Exceed allow 2,500 files.
- A download notification does not mean the mailbox has been imported into an email program.
Frequently asked questions
What is an email archive?
It is a copy of a mailbox saved as a file. PST is Outlook’s archive file. OST is Outlook’s working copy. MBOX is a file format used by Thunderbird and Apple Mail to store an email folder. EML is a single message. We send the file without opening it. We don’t compose a new email.
Are PST and OST the same?
No. PST is an archive exported to share with someone else. OST is the working copy used while Outlook is running. It may be locked while the program is open and may be incomplete. Export a clean PST file yourself. We don’t convert OST to PST or repair damaged files.
Can I transfer MBOX files too?
Yes, they download as they are. We don’t convert Thunderbird or Apple Mail archives into Outlook files. The recipient opens the archive in their own program. Include the name of the program it came from in your note.
Can I save each message as a separate file?
You may hit the file count limit. EML is a single message. A mailbox built up over years can contain tens of thousands of files. Free transfers stop at 500 files. SendGB Extra and SendGB Exceed stop at 2,500 files. Transfers over the limit cannot be completed. Export the mailbox as a single PST or MBOX file. We don’t merge the parts.
Do you connect to my mailbox?
No. We don’t access Outlook, Gmail, or your company’s mail server. You export the archive yourself. There is no Gmail or Outlook add-on. You send the exported file.
Do you read the messages?
No. We leave subjects, attachments, and contacts untouched. An archive may contain someone else’s messages, contracts, and identity documents. Protect the link with a password. Send the password separately from the link. If the file has its own password, you keep control of that too. Don’t confuse the two. We don’t remove content from the archive.
Can the recipient open the archive on the download page?
No. PST, OST, and MBOX files do not open on the download page. We don’t extract attachments from the mailbox. A PDF you include alongside it may be displayed. A short .txt note may open. The recipient imports the archive into their email program. No account is needed to download.
Why won’t Gmail accept my archive?
Gmail does not accept attachments over 25 MB, and Outlook does not accept attachments over about 20 MB. A mailbox can be hundreds of times larger than this limit. Don’t attach the archive to a new email. A link is not an attachment. There is no add-on.
Will I be notified when the recipient starts downloading?
Yes, if you entered your email address. With email delivery, you are notified once per recipient. With link delivery, you are notified once per transfer. The notification tells you that downloading has started. It does not confirm that the entire file has downloaded. It does not mean the mailbox has been imported into Outlook or Thunderbird.
Which transfer option do I need?
An archive within the 5 GB and 500-file limits can be sent free. Free transfers over 250 MB stay available for 7 days. Free transfers up to 250 MB stay available for up to 90 days. A larger mailbox needs SendGB Extra: 500 GB per transfer, 2,500 files, 1 TB of storage, starting at €29.90 per year, with files kept for up to 1 year. For a single archive over 500 GB, SendGB Exceed is enough: no membership, 2,500 files, and a 1 TB transfer for €9.99. The code can be used once and is valid for 1 year. The link stays available for 7 days. More than 1 TB will not fit in a single transfer. Don’t make this link your company’s only archive.
Send a download link, not an email archive attachment
A small folder may fit within 5 GB. A mailbox built up over years can be sent with SendGB Extra up to 500 GB, or with SendGB Exceed up to 1 TB in a single transfer. Don’t make this link your company’s only archive.
Start sending