You attach the file, hit send, and watch the progress bar crawl to 99% before it fails: "Message size exceeds limit." So you zip it, split it, or drop it on a free transfer service that expires before the client gets around to downloading it.
Attachments were never designed for the files businesses actually send. This guide shows you how to replace that habit with link-based sharing: the setup, the folder structure, the permissions, and the follow-up routine that makes it stick.
TL;DR
Most email systems cap messages at roughly 20–25 MB, and encoding inflates your file by about a third before it's even sent. Share a link instead: upload once, control who can open it, set an expiry, and update the file without resending. Then archive and revoke access when the project ends.
Why Attachments Fail
Email was built for text, not multi-megabyte files, and three things go wrong when you use it as a file transfer system.
Size limits stop you. Gmail and Yahoo Mail cap outgoing messages at about 25 MB, Outlook.com at around 20 MB, and many corporate mail servers are stricter still. The lowest limit between you and your recipient is the one that applies, so a message can pass on your side and bounce on theirs.
Encoding makes files bigger. SMTP transmits attachments as text using Base64 encoding, which inflates them by roughly a third. A 20 MB file becomes about 27 MB on the wire, putting it over a 25 MB limit before it leaves your outbox.
Every copy is stored forever. Send a 15 MB file to ten people and ten mailboxes each store a full copy. Multiply that across a year and you'll understand why inboxes hit their storage quota. On a plan with 5 GB per mailbox, attachments are usually what fills it; a link, by contrast, costs a few hundred bytes.
There's a control problem too. Once an attachment is sent, you can't take it back, update it, or see whether it was opened. A link can be revoked, replaced, and restricted.
What You Need Before Starting
Your provider's attachment limit, and ideally a sense of your clients' limits.
A list of what you actually send: contracts, reports, design files, video, data exports.
A file storage service your business controls, on your own accounts rather than a personal one. NevTan Drive shares storage with NevTan Mail, so files and email live in the same account.
A check on client access. Some regulated organizations block unfamiliar domains or link types, so ask before you change everyone's workflow.
A naming convention, so a file is still findable a year later.
Email on your own domain, so your messages and links come from your brand rather than a free consumer address. See business email vs personal email.
Step 1: Audit What You're Sending
Open your sent folder and search for large attachments. In Gmail, has:attachment larger:5M finds them quickly; most clients have a similar filter.
Note three things: the biggest files you send, which ones you send repeatedly, and which contain sensitive information like contracts, invoices, or personal data. Those three lists tell you what to move to links first. Repeat sends are the easiest win, because a single shared folder replaces the whole cycle.
Pro tip: While you're in there, check how much of your mailbox storage attachments occupy. It's usually most of it.
Step 2: Choose Your Sharing Method
Four options cover almost every case:
Method | Best for | Watch out for |
|---|---|---|
Cloud storage link | Ongoing projects and repeat sends | Getting permissions right |
Transfer service (e.g. WeTransfer) | One-off large media files | Free tiers expire after a few days |
Client portal | Law, finance, healthcare, anything confidential | Setup effort and client onboarding |
Attachment | Small files: a one-page PDF, a signed form | Size limits and no control after sending |
Attachments aren't banned. For a 200 KB invoice, an attachment is simpler for everyone. The rule of thumb: anything over a few megabytes, anything sensitive, and anything you'll send more than once should be a link.
Pick one primary method and one fallback, then write it down so everyone on the team sends files the same way.
Pro tip: Test your chosen method with a genuinely large file, and have someone outside your organization open the link. Permission problems only appear from the outside.
Step 3: Set Up Folders and Permissions
Mirror your client list in your folder structure:
/Clients/ClientName/ProjectName/
├── Deliverables
├── Source files
└── ArchiveThen set permissions deliberately:
View-only by default. Grant edit rights only when someone genuinely needs to collaborate.
Share the specific folder or file, never the parent folder that contains every client's work.
Restrict to named recipients for anything confidential, rather than "anyone with the link."
Set an expiry where your tool supports it. Thirty days suits most projects.
This is also where you prevent the classic disaster: sharing a folder that contains another client's files. Structure and view-only defaults make that mistake much harder.
Step 4: Send the Link Well
Upload, copy the link, and write a short message that tells the client exactly what they're getting:
"Hi Sarah, here's the Q3 campaign report (PDF, 14 MB): [Q3 campaign report]. The link works until 30 November. Let me know if you'd like the editable version."
Three details make the difference: what the file is, its format and size, and when access ends. Hyperlink the text rather than pasting a raw URL, which looks cleaner and is less likely to get mangled.
One caution: links from unfamiliar domains can look like phishing, which is exactly what your clients should be suspicious of. Sending from your own domain with properly configured authentication helps, and a quick heads-up in the message body ("this link goes to our Drive") avoids the awkward "is this really from you?" email. Our guide to protecting your company from business email compromise covers why clients are right to be cautious.
Step 5: Follow Up, Then Clean Up
If your tool shows access activity, use it: no opens after a couple of days usually means the message got buried, not that the client is ignoring you. A short "just checking this reached you" is enough.
Then close the loop when the project ends:
Move files to the archive folder.
Revoke links that are no longer needed.
Remove access for people who have left the client's team, or yours.
This last step is where most teams fail. Links created for a project three years ago quietly keep working unless someone turns them off. Put a recurring monthly "link audit" in your calendar, and fold it into your email retention policy and your offboarding process.
Example: A 12-Person Design Studio
The following is an illustrative scenario.
A branding agency sends client deliverables as attachments. Their typical project file is around 45 MB, so they zip and split, or use a free transfer service whose links expire in days. Clients report broken links weekly, and the team spends hours re-sending files they've already sent.
They switch to a structured cloud folder per client, with view-only permissions and 30-day expiries, and they email links instead of files. Repeat sends disappear, because clients bookmark the project folder and the team updates the file in place. Mailbox storage stops filling up, and when a project ends, the monthly link audit closes off access.
The change costs nothing beyond an hour of setup and a short note to clients explaining the new process.
How to Choose for Any Given File
Small and simple (under a few MB, not sensitive): an attachment is fine.
Large media (100 MB+): cloud storage or a transfer service with resumable uploads.
Confidential (contracts, financial or personal data): restricted access to named recipients, with an expiry, and encryption in transit and at rest.
Ongoing project: a shared folder the client can bookmark beats a new link each time.
Non-technical recipient: one link, clear instructions, no accounts to create.
Regulated industry: confirm your method meets your obligations before you send anything. Our security page covers how NevTan handles data.
When in doubt, pick the option that gives you the most control, not the one that's fastest today.
Common Mistakes
Links with no expiry. A permanent link is a permanent liability. Set one, and revoke manually when the project ends.
Edit access by default. Clients accidentally overwriting or deleting your master file is a bad afternoon. Default to view-only.
Sharing a parent folder. One careless share can expose every client's work. Share the specific folder.
Using personal cloud accounts. Business files in a personal account leave the business when the employee does. Keep files in accounts the company controls.
Not saying the link expires. Clients who discover it the hard way just ask you to resend.
Never cleaning up. Old links outlive the relationships they were made for. Audit monthly.
FAQ
What's the maximum email attachment size?
Gmail and Yahoo Mail allow about 25 MB, Outlook.com about 20 MB, and many corporate servers less. Base64 encoding adds roughly a third to the file size, so the practical limit is lower than the number suggests, and your recipient's limit matters as much as yours.
Why did my email bounce when the file was under the limit?
Because encoding inflated it past the limit, or because the receiving server has a stricter cap than yours.
Is sharing files by link safe?
Yes, when configured properly: restrict access to named recipients, set an expiry, use view-only permissions, and choose a provider that encrypts files in transit and at rest.
How do I send files larger than 1 GB?
Use cloud storage with resumable uploads, or a transfer service built for large files. For recurring large files, a shared folder is easier for everyone.
Should I ever attach files?
Yes. For small documents like a one-page invoice, an attachment is simpler. Save links for large, sensitive, or repeatedly sent files.
What if a client can't open my link?
Check whether it expired, whether their organization blocks the domain, and whether the permissions allow their email address. Keep one fallback method ready.
How long should links stay active?
Thirty to sixty days for active projects, shorter for one-off sends. Revoke when the work is done.
Do attachments affect deliverability?
Large messages are more likely to be rejected outright by size limits and slower to deliver. Attachment types matter too, since many organizations block executables and macro-enabled files. Links avoid both problems.
Keep Your Inbox for Messages and Your Files in Drive
Attachments fill mailboxes, break at size limits, and can't be recalled. Links stay small, stay current, and stay under your control.
NevTan Mail gives you secure, ad-free business email on your own domain with a calendar, meetings, and admin controls, plus up to 10 mailboxes free forever. NevTan Drive lets you store, organize, preview, and share files securely, with storage shared across your NevTan account, so the files you send clients and the email you send them live in one place. Need signatures on those documents? NevTan Sign handles that too.
