Outlook attachment size limit.
Outlook refused your attachment because the message would have crossed the 20 to 25 MB ceiling. That cap is older than Outlook itself, baked into SMTP. The web client pushes you towards OneDrive, but OneDrive sharing pulls the recipient into a Microsoft account flow, and the file sits in your storage forever after. There is a cleaner path: host the file outside email and paste a plain HTTPS link into your message. The upload widget below gives you that link in seconds, with no signup on either side.
Drop a file.
Free up to 100 MB. We will give you a link in seconds.
or click anywhere to choose
No email means no recovery. If you lose this link, we can't get you back to this file.
Price scales with file count, up to 25 files. Shown once. 7-day expiry.
What is happening
Outlook.com caps attachments at 20 MB per message. Outlook for Microsoft 365 defaults to 25 MB and can be raised to 150 MB by an admin.
Outlook follows the SMTP convention of a small per-message attachment ceiling. The Outlook.com web client refuses messages over 20 MB outright and prompts you to share via OneDrive. The Microsoft 365 desktop client honours whatever cap your tenant admin has set, but mail servers along the path may impose their own ceilings, so the safe default is 20 MB.
Common workarounds
Here is what most people try first, and where each option falls short.
- Use the OneDrive link Outlook offers
- Click attach, choose the big file, accept the OneDrive upload prompt.
- Downside. Recipient needs a Microsoft account or a tenant-issued sign-in to open the link unless you flip the share to anyone with the link. The file also sits in your OneDrive forever unless you remember to delete it.
- Compress to a zip
- Right-click, compress, send the archive instead.
- Downside. Video, photos, and PDFs are already compressed. The zip is barely smaller. The recipient still has to unpack it before opening anything.
- Ask your admin to raise the limit
- File a ticket with IT to bump the tenant attachment cap.
- Downside. Even at 150 MB, recipient servers may reject the message. And many corporate IT teams will not raise the cap for one-off sends.
- Switch to a transfer service like WeTransfer
- Upload to WeTransfer, paste the resulting link.
- Downside. Free tier requires entering an email and the recipient's email every send. Paid tiers are a monthly subscription you may not need.
The cleaner fix
Drop your file on quik.space, copy the link, paste it into your Outlook message. Recipient downloads in two clicks, no Microsoft account, no permissions dance. Free up to 100 MB. The file auto-deletes after 72 hours so it does not linger in any cloud you have to clean up later.
The upload widget at the top of this page is the same one on the homepage. Drop the file, copy the link, paste it where you wanted to attach. See pricing for the full table or how it works for the three-step explainer.
What we will not do
We do not read your file. We do not train AI on your file. We do not sell your file. Every upload is encrypted in transit over HTTPS and at rest. The share ID is an 8-character random string with roughly 218 trillion combinations, so the link is practically unguessable. After 72 hours plus a 7-day grace period, the bytes are permanently purged from storage and cannot be recovered.
Frequently asked
- Why is Outlook so strict about attachment size?
- Microsoft and most enterprise mail servers cap at 20 to 25 MB by default to protect inbox storage and keep SMTP traffic predictable. The Outlook desktop client may show a higher local cap but the receiving server often enforces a lower one.
- Is OneDrive my only option for big attachments in Outlook?
- No. Any link works. Paste a quik.space link in the message body and you skip the OneDrive permissions step entirely.
- Will the link still work if my recipient uses Gmail or Apple Mail?
- Yes. quik.space links are plain HTTPS URLs and work in any mail client and any browser.
- Does Outlook block links to file-sharing services?
- Some corporate tenants flag specific domains in spam filters. quik.space is not on common blocklists, but if your tenant blocks unfamiliar domains, ask IT to allow quik.space.
- Can I send multiple files at once?
- Yes. Up to 3 files per drop is free, or pay $2 for a bulk batch of up to 25 files.
Related
Hitting a different size cap? Here are nearby problem-state guides.