How to send large files in Outlook using OneDrive

This guide shows you how to send a file that is too large to attach to an email — drawings, photo sets, PDFs, videos, ZIP files — by uploading it to OneDrive and sending a link instead. Use this if Outlook says the attachment is too large, if your email bounces back, or if the message just sits in your Outbox and never sends.

A OneDrive link keeps the email tiny, works for files far bigger than email allows, and lets you change or revoke access after you hit Send.

When to use a link instead of an attachment

File size	What to do
Under 10 MB	Attach normally
10–20 MB	Attach only if the recipient is known to accept it; a link is safer
Over 20 MB	Send a OneDrive link
Any size, if the file will keep changing	Send a OneDrive link so everyone sees the current version

Why 20 MB and not 25 MB: our mail system's limit is on the whole message, not just the file. Email adds roughly 33% overhead when it encodes an attachment, plus your signature and any images. A 20 MB file can easily become a 27 MB message and get rejected. The recipient's mail system has its own limit too — many outside companies still cap at 10–25 MB, and the bounce can come back hours later.

Note: Our maximum message size is currently 25 MB send/receive. If you are frequently near the limit, contact IT rather than splitting files across several emails.

Prerequisites

• You are signed in to Outlook and OneDrive with your company account
• The OneDrive icon (cloud) in your system tray shows a checkmark, not a red X or "paused"
• You know whether the recipient is internal (a coworker) or external (a GC, architect, vendor, or customer) — this changes which permission you pick

Steps

Pick the section that matches the Outlook you use. Not sure? In classic Outlook there is a File menu in the top-left corner and an Attach File button on the ribbon. New Outlook has a slimmer toolbar with no File menu, and a Settings gear in the top-right.

Option A — New Outlook for Windows (and Outlook on the web)

1. Start your message

Select New mail, or open a Reply or Forward. You will only see the Insert group on the ribbon once a message is open.

2. Select Attach File

On the Message tab, select Attach File (the paperclip).

3. Choose the file

• Suggested files — your three most recent cloud files
• OneDrive — browse your OneDrive or a SharePoint/Teams site
• Browse this computer — pick a file off your PC

If you picked the file from OneDrive or SharePoint, skip to step 5. You should see the file appear as an attachment chip below the subject line with a small cloud or link icon on it.

4. If the file came from your computer, upload it to OneDrive

1. In the message, select the down arrow on the attachment.
2. Choose Upload to OneDrive, then choose the destination (your work OneDrive, not a personal account).
3. Wait for the upload to finish. The attachment changes from a plain file to a link.

5. Set who can open the link

Select the arrow at the right of the attachment name and choose one of:

Permission	Who can open it	Use it for
Organization can Edit	Anyone at the company, and they can change the file and reshare it	Internal working files
Organization can View	Anyone at the company, read-only, no resharing	Internal reference documents
Recipients can Edit	Only the people on this email; they can change it and reshare	Rare — a document you want a specific person to mark up
Recipients can View	Only the people on this email, read-only	Default choice for anything going outside the company

By default in a business tenant, everyone inside the organization can edit the file, so change this before you send when the file is going to an outside party.

6. Check for the access warning

If Outlook can tell your recipients won't be able to open the file — for example it sits in a SharePoint site they have no rights to — the link is highlighted in red with a warning icon. Select Manage access and fix the permission before sending. Do not ignore this; the email will send fine and the recipient will hit a wall.

7. Write your message and send

Say what the file is in the body — "Link to the shop drawings for Level 3" — because a link chip is easier to miss than a paperclip.

Option B — Classic Outlook for Windows

1. Start your message

Select New Email, or Reply / Forward.

2. Select Attach File

On the Message tab, in the Include group, select Attach File.

3. Choose where the file lives

• Recent Items — files you worked on lately
• Browse Web Locations — OneDrive, SharePoint sites, or Teams document libraries
• Browse This PC — opens File Explorer for a local file

4. Choose link or copy

• If you picked the file from Browse Web Locations, Outlook asks whether to Share link or Attach as copy. Choose Share link.
• If you picked the file from Browse This PC, it attaches as a full copy. To convert it: select the down arrow on the attachment, choose Upload, and pick your OneDrive location. Outlook uploads the file and replaces the attachment with a link.

5. Set permissions

Select the down arrow on the attachment and use the permission options (same four choices as the table in Option A). For external recipients, set view-only access for just the recipients.

6. Write your message and send

Option C — Share from OneDrive directly, then paste the link

Use this for very large files, whole folders, or when Outlook's upload keeps failing.

1. In File Explorer, right-click the file or folder inside your OneDrive folder and select OneDrive > Share. (Or go to the OneDrive web app, select the file, and choose Share.)
2. Select the settings/gear or the current permission text at the top of the share box to change who the link works for. Choose People you choose or People in Allegheny Millwork rather than Anyone with the link unless you have a reason.
3. For outside recipients, clear Allow editing, and set an expiration date if the file is sensitive.
4. Select Copy link.
5. Paste the link into your Outlook message and add a line of context.

Tip: If the file is not already inside your OneDrive folder — for example it is on a mapped network drive or the desktop of a server — copy it into your OneDrive folder first and wait for the green checkmark. You cannot share a link to a file that only exists on a file server.

Sending several files at once

• Related files, one delivery: put them in a folder inside OneDrive and share the folder link. One link, everything inside it.
• Recipient wants one download: select the files, right-click, Compress to ZIP file, then share the ZIP. ZIP is better for outside parties who just want to save everything locally.
• Avoid sending five separate links in one email. Recipients open one and miss the rest.

Verify it worked

1. Before sending, confirm the attachment shows a cloud/link icon rather than a plain file icon, and that no red warning appears.
2. After sending, open the message in Sent Items and select the attachment arrow > Manage access. The list should show the people you expect.
3. For an important external send, open the link in a private/incognito browser window. If it asks you to sign in with an account the recipient doesn't have, the permission is too tight — fix it and resend.

Common issues

Problem	Fix
Recipient sees "You need permission to access this item" or a sign-in prompt they can't get past	The link is restricted to the organization, or their email address differs from the one you shared to. Reopen the file's sharing settings, add their exact address, or switch to a recipients-can-view link. Forwarded links do not carry permission to the new person.
Upload to OneDrive is greyed out	The file is not in a location Outlook can upload from, or OneDrive is not signed in / is paused. Check the OneDrive cloud icon in the system tray.
The link drops into the message body as plain blue text instead of an attachment chip	This still works. If you want the chip, remove it and re-attach using Attach File > OneDrive.
The message is still too large after linking	Something else is heavy — usually pasted screenshots, a photo-heavy signature, or another leftover attachment. Remove the remaining attachments and link those too.
The email bounced with "message size exceeds the limit" even though it looked small	The recipient's mail system rejected it, not ours. Use a link, and confirm the bounce text names their domain.
The recipient says the file is wrong or out of date	A link always shows the current version. If you edited the file after sending, they see the edit. Send a copy instead if you need to freeze a version — for example an issued drawing set or an executed contract.
You moved, renamed, or deleted the file after sending	The link breaks. Leave shared files where they are, or re-share from the new location.
External sharing appears to be blocked entirely	Some sharing options are restricted by policy. Contact IT rather than emailing the file from a personal account.

Good habits

• Set expiration dates on links to outside parties for anything price-sensitive or contractual.
• Put team files on SharePoint/Teams, not in your personal OneDrive. Anything shared from your OneDrive becomes inaccessible when your account is disabled.
• Never use a personal Dropbox, Google Drive, or personal OneDrive account for company files, even once, even for a file that seems harmless.
• Say what the link is in the email body. "See attached" tells a recipient nothing when the attachment is a link.