How Can You Easily Fix Outlook Attachment Send Failure and Boost Your Email Success?

Why Are Outlook Emails with Attachments Not Delivering? Key Steps to Solve This Worrying Problem

Sometimes you have an email with an important attachment, and it never reaches its recipient. This can feel discouraging, especially when your work demands speed and reliability. Let’s go through simple, step-by-step advice to fix Outlook not sending emails with attachments. These methods use clear language. Anyone can follow these steps.

Quick Checks

Is your internet stable? Slow or dropping connections can block large emails. Test your email on another Wi-Fi or switch to mobile data.

Try resending. Often, sending the email a second time solves the problem for many users.

Solution 1: Exchange Server Outage

Wait and try again in one or two hours. Outlook servers can have short-term issues outside user control. Most outages resolve on their own.

Solution 2: Run Outlook in Safe Mode and Disable Add-ins

Add-ins can block attachments without warning.

Start Outlook in Safe Mode:

1. On your keyboard, press Windows + R.
2. Type outlook.exe /safe and press OK.

Try sending the attachment.

1. If it works, exit. Start Outlook normally.
2. Go to File > Options > Add-ins.
3. Click Go next to “Manage COM add-ins.”
4. Uncheck everything. Click OK.
5. Restart Outlook. Try again.

Solution 3: Check Attachment Size and Type

The size limit for attachments is 25 MB per email (including attachments and message text). Even a file less than 25 MB by itself can cross the size limit when encoded.

Some file types like .exe, .bat, .js, or files inside zipped folders can be blocked for being unsafe. Try removing or renaming these file types, or use a service like OneDrive and send a link.

Solution 4: Disable Antivirus Temporarily

Antivirus software blocks files it thinks are risky—even safe attachments can get held back.

Temporarily pause antivirus and try to resend.

1. On Windows, open Windows Security.
2. Go to Virus & Threat Protection > Manage Settings.
3. Turn off real-time protection and (if present) cloud protection.

If you use Office 365 or Exchange, ask an admin to add this header in mail flow rules: X-MS-Exchange-Organization-SkipSafeAttachmentProcessing: 1 to help bypass certain scans.

Solution 5: Repair Your Outlook Profile

A damaged profile can stop attachments from sending.

1. Open Outlook.
2. Tap File > Info > Account Settings.
3. Choose your account and click Repair.
4. Follow the steps shown.

Solution 6: Compress Files

Use tools like WinZip, WinRAR, or 7-Zip to make your attachment smaller. Smaller files send faster and are less likely to hit size or security limits.

Compressed files should not contain any forbidden types inside, such as .exe. If so, consider renaming or using a secure transfer service.

Other Helpful Tips

• If sending still fails, use Outlook Web Mail (browser) or another device. Sometimes, desktop issues do not appear in webmail.
• Try using OneDrive or Google Drive to upload your file and share a link, especially for large or sensitive files.
• Double-check that the recipient’s address is correct and their mailbox is not full or rejecting attachments due to filter rules.

Additional Notes

• Sometimes, updating Outlook or creating a new profile can fix issues that keep coming back.
• Attachment issues can also result from mailbox configuration problems, like wrong time zones in shared mailboxes.
• File type limits and spam filters can change over time, especially if your company changes email policies or adds new security software.

These steps solve Outlook email and attachment issues for most senders. Persistent problems are rare and often tied to bigger server issues or company-wide policy changes. With these straightforward steps, you can restore your emailing confidence and keep your work flowing smoothly.