You're ready to send a file and hit an error — "attachment too large," the upload stalls, or the message won't go through. The cause is usually simple: email providers and apps enforce strict size limits, and the right fix depends on what you're sending and who receives it.
Quick Answer
Compress if it's a folder of documents or mixed files. Use a cloud link if the file is already compressed or too big to shrink. Use a transfer service for one-off sends over a few gigabytes. Start with the first option that fits your file — the others are backups.
Why This Happens
Most email services cap attachments between 20 and 25 MB. Messaging apps vary: WhatsApp around 100 MB, Telegram up to 2 GB, iMessage depends on carrier and storage. Even if your file is 500 MB, the sending app may reject it before it leaves your device.
Another common cause: the file is already in a compressed format. JPG, MP4, PDF, and ZIP files rarely shrink much further because they're already packed efficiently.
Solutions, Easiest First
1. Compress the File
Best for folders, documents, spreadsheets, and anything that isn't already compressed.
- Windows: right-click the folder → Send to → Compressed (zipped) folder.
- Mac: right-click the folder → Compress.
- Try sending the .zip file. If it still exceeds the limit, move to the next option.
Limitation: ZIP rarely reduces photos, videos, or existing PDFs by much. If the compressed size is close to the original, don't keep trying different zip tools — switch to cloud sharing.
2. Upload and Share a Link
Better than compressing when the file won't shrink. The recipient downloads from the cloud instead of receiving the file directly.
- Google Drive: Upload → right-click → Share → change to "Anyone with the link." Paste the link in your email or message.
- OneDrive: Upload → Copy link → send.
- Dropbox: Upload → Copy link → send.
Watch free storage: Google gives 15 GB shared across Drive, Gmail, and Photos; OneDrive 5 GB; Dropbox 2 GB. If you're near your limit, this won't work until you free space.
3. Use a File Transfer Service
Good for one-off sends when you don't want to upload to your own cloud.
- WeTransfer: Free up to 2 GB, no account needed for basic use.
- Send Anywhere: Free tier available, supports larger files with registration.
- Firefox Send: Discontinued — do not use replacements claiming to be Firefox Send.
Upload the file, get a download link, and send the link. Most services expire the link after a few days.
4. Split a Large File
If the file must be sent as an attachment and keeps failing:
- Compress the file into a ZIP.
- Use an archiving tool to split the ZIP into parts under the size limit (e.g., 20 MB chunks).
- Send all parts and tell the recipient to extract the first one — the rest should unpack automatically.
This adds friction for the recipient, so prefer cloud links or transfer services when possible.
5. Reduce the File Itself
When the above options aren't available or the recipient needs the actual file.
- Images: Use Preview on Mac or Photos on Windows to resize, or an online tool like TinyPNG.
- Video: Handbrake (free) or an online compressor to lower resolution or bitrate.
- Documents: Remove embedded images, convert to PDF, or delete unnecessary pages.
Warning: Lowering quality may make the file unusable for the recipient. Confirm they need the full resolution before压缩.
If It Still Doesn't Work
- ZIP didn't reduce size? The files are likely already compressed. Skip ZIP and use a cloud link or transfer service.
- Cloud link blocked? Some corporate or school networks block external links. Try a transfer service or ask the recipient to check their spam/firewall.
- Upload keeps failing? Check your internet connection, try a different browser, or reduce file size before uploading.
- Recipient can't download? Make sure link permissions are set to "anyone with the link," not just people in your organization.
Important Warnings
- Don't upload sensitive documents to random transfer sites without checking their privacy policy.
- Links expire — confirm the recipient downloaded the file if it's time-sensitive.
- Large transfers can fail mid-upload; if the service offers resumable uploads, enable it.
Final Guidance
For a folder of documents, ZIP first. For a single large file, use a cloud link. For a quick one-off over 2 GB, use WeTransfer or similar. If the recipient can't access the link, fall back to splitting the file or reducing its size.
Start with the option that matches your file type and size, and stop once the send succeeds — there's no need to try every method.