Quick Answer
What happens when an email attachment is too large?
Email providers limit the total size of a message, including the email body, attachments, and encoding. If the total message exceeds the provider's limit, the email can fail or bounce. When a file is too large, the most reliable alternative is to upload it to cloud storage and send a share or download link instead.
Attachment Size Limit Overview
You may need to send files by email, but large attachments can cause messages to fail or bounce before they reach the recipient.
Email providers limit total message size, which includes the email body, attachments, formatting, and encoding. If the total message exceeds that limit, the message can fail or bounce.
When that happens, you may see a size-related error notice in BizStackPro, your conversations, or your email logs, and the recipient may never receive the message.
Common size-related error messages can include:
- “Attachment size exceeds the allowable limit”
- “552: Message size exceeds maximum permitted”
- “System Undeliverable, message size exceeds outgoing message size limit”
- “The size of the message exceeds the global size limit. Reduce the message size and try again.”
The limit applies to the entire message
Attachment limits depend on the email provider. Many sending services cap the total message size around 25MB; for example, Mailgun commonly enforces a 25MB maximum message size. Large PDFs, images, or videos can reach that limit quickly.
Attachment Limits at a Glance
Before You Begin
Check the size of the files you plan to send and consider whether attaching them directly is the best option.
- Check the file size before attaching it to the email.
- Remember that encoding and message content can increase the total message size.
- Consider using a cloud link for large PDFs, images, videos, or other large files.
- Make sure any cloud file permissions allow the recipient to access the file.
- Review size-related bounce or error messages if a message fails.
Step 1: Handle Large Files with Shareable Links
You cannot force an email provider to accept a message that exceeds its size limit. The reliable alternative is to share the file through a link.
Upload the File
Upload the file to a cloud storage service such as Google Drive, Dropbox, or OneDrive.
Set the File Permissions
Make sure the recipient has permission to view or download the file.
Copy the Share Link
Copy the file's share or download link from the cloud storage service.
Add the Link to Your Email
Paste the link into the email instead of attaching the large file directly.
Send the Email
Send the lighter message without the oversized attachment.
Simple large-file workflow
Upload → copy share link → paste the link into your email → send. This keeps the message smaller and helps avoid attachment-related bounces.
Step 2: Understand the Available Upload Options
BizStackPro supports different ways of working with files, while the exact behavior can depend on the email provider, channel settings, configuration, and file size.
Device Uploads
Files can be attached from your device when the file and total message size remain within the provider's limits.
Media Library Support
BizStackPro also supports selecting files from the media library where available.
Link-Based Sharing
Depending on your configuration and file size, larger files may be converted into shareable links to help prevent oversized messages.
Video Preview Support
Some setups may generate preview thumbnails for video content to make video links easier for recipients to identify and access.
Exact behavior can vary
Attachment processing can depend on your email provider, channel settings, configuration, and the file itself. Attachments may also become larger during email encoding.
Why Attachment Size Management Matters
Keeping email messages reasonably sized can reduce delivery problems and make files easier for recipients to access.
Fewer Bounces
Smaller messages reduce the chance of size-related delivery failures.
Better Deliverability
Avoiding repeated delivery failures can support a healthier email-sending workflow.
Faster Sending
Lighter messages can send and load faster than emails carrying large attachments.
Better Recipient Experience
Shareable links can be easier to access than bulky attachments, especially on mobile devices.
Email Attachment Best Practices
Frequently Asked Questions
What is the maximum file size I can attach to an email?
What happens if my email exceeds the file size limit?
How can I send larger files if they exceed the email attachment limit?
What improvements have been made to the file upload process?
How does the upload feature benefit me?
Continue Learning
Continue with related guides for attaching files, understanding email errors, and improving email deliverability.
