Sending Large Attachments via Drive

Most email systems quietly reject attachments larger than about 25 MB. Some get stricter — corporate Outlook deployments often cut you off at 10 MB. The result: you attach a 30 MB PDF, click Send, and 20 minutes later get a delivery failure from a server you've never heard of.

TrekMail webmail solves this by quietly routing large attachments through Drive. The recipient sees a normal-looking message with a clean download link instead of an attachment that bounces. No setup required from you, no acceptance step required from them.

How auto-routing works

Compose a message in webmail and attach files however you normally do — paperclip button, drag-and-drop into the composer, paste an image from your clipboard. Webmail measures each file as it's added.

If a file is under 18 MB, it stays an attachment. The recipient sees a paperclip icon and downloads the file inline through their email client.

If a file is 18 MB or larger, webmail uploads it to your Drive in the background and replaces the attachment with a public download link. The composer shows the file as a "link attachment" — same row position, same filename, but with a small link icon and the note "Will be sent as a download link."

The 18 MB threshold matches what most email systems will reliably accept. Going higher risks bounces from strict recipients; going lower would route too many normal-sized attachments through Drive unnecessarily.

What the recipient sees

The email itself looks normal. Subject, body, signature — everything you wrote. Where an attachment would normally appear, the recipient gets a small inline block with:

• The filename
• The file size
• A "Download" button

Click the button and the file streams to their browser. No login, no acceptance, no third-party redirect. The download happens from trekmail.net directly.

The message renders identically across email clients — Gmail, Outlook, Apple Mail, mobile apps — because the link is plain HTML. There's no special MIME type or proprietary format.

Where the file ends up in Drive

Auto-routed attachments land in a special Email attachments folder inside your Drive. This keeps them separate from files you've intentionally organised.

The folder is created automatically the first time you send a large attachment. You can navigate to it like any other folder, see what's there, delete files you no longer need.

Files in the email-attachments folder still count against your storage pool the same as any other file. If you send dozens of large attachments and never clean up, they accumulate.

Download caps

Each auto-created link defaults to a 100-download cap. After 100 successful downloads, the link stops working — the recipient (or anyone they forwarded it to) sees the "no longer available" page.

100 is generous for normal use. A typical email has one recipient who downloads once. Even with three or four forwards and a couple of recipients on each, you're looking at a dozen downloads. 100 leaves headroom but caps the damage if a link leaks.

You can override the cap from the composer when you compose. Look for the link options on the attached file row — there's a download-cap field and an expiry-date field, both blank by default (meaning the cap stays at the 100 default and there's no expiry). Set them if you want stricter or looser behaviour for a specific message.

Sending a file already in Drive

You can also send a file that's already in your Drive without uploading it again. In the composer toolbar, click the Drive icon. A folder picker opens — navigate, pick the file, and a public download link is added to the message. The file isn't re-uploaded; the link points at the existing copy.

This is the right approach for files you keep on hand and send regularly: templates, standard agreements, brand assets, deliverables you've already prepared. The recipient sees the same experience as an auto-routed attachment — a clean download link in the message body, with the same default 100-download cap.

What to do when you don't want auto-routing

Sometimes you want a file to be a real attachment regardless of size — maybe the recipient explicitly asked for it as an attachment, or maybe you're sending to a system that requires inline attachments.

For files under 18 MB, auto-routing doesn't apply, so you're already there.

For files 18 MB and larger, your options are:

• Compress to under 18 MB if possible. ZIP archives, smaller image dimensions, lower-bitrate video.
• Split into multiple files under 18 MB each and attach them all.
• Send the file via a different channel that supports the size (Drive's public share links work even outside the composer; you can also drop in Slack, SFTP, etc.).

There is no per-message override that forces a large file to be a real attachment — most email systems would reject it anyway.

Pool implications

Auto-routed attachments use storage in your pool. A 30 MB attachment uses 30 MB until you delete it from the email-attachments folder. The recipient downloading the file does not duplicate the storage.

If you send a lot of large attachments, the pool fills up over time. The fix is the same as any other Drive consumer: delete what you don't need, empty Trash, or expand the pool.

You can also set a habit: every quarter, open the Email attachments folder and clear out anything older than 90 days. Most files you sent six months ago aren't worth keeping forever.

Behaviour outside webmail

This auto-routing applies to the TrekMail webmail composer only. If you send email from an IMAP/SMTP client (Outlook, Apple Mail, Thunderbird, etc.), the client builds the MIME message itself — TrekMail's SMTP relay forwards what arrives.

In that case:

• Attachments are real MIME attachments, regardless of size.
• TrekMail's SMTP submission accepts up to its own message size cap (large but finite).
• The recipient's email system enforces its own attachment-size policies.

If you regularly send large files from a desktop email client, the cleanest workflow is: upload to Drive first, generate a public share link, paste the link into your message body. Same recipient experience as the webmail auto-routing, just done by hand.

Common scenarios

"My recipient says they can't download the file." Check the link in the manage-links view of that file in Drive. The likely culprits: link expired, download cap hit, file moved to Trash and 30-day clock expired. Create a fresh link if needed.

"The file appears as an attachment in some clients but a link in others." That doesn't happen — the message body contains a link in HTML and a textual reference in the plain-text part. Both clients see the link, just in different visual styles. There's no client-specific switching.

"I want to send the same large file to 50 people without 50 different links." Send a single message with the file attached; all 50 recipients see the same link. Or, use a share link and paste it manually into one message you BCC to 50 people.

"My recipient's company strips download links from emails." Some corporate filtering systems treat any external link as suspicious. Workaround: shrink the file or send via a different channel. There's no setting in TrekMail to bypass recipient-side filtering.

What's next

• Public Share Links — the underlying link mechanism, including manual creation and full options.
• Uploading Files to Drive — preload Drive with templates and brand assets so the Drive picker is ready when you compose.
• Pooled Storage Quotas Explained — how attachments factor into your pool.