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Outlook Issues and Troubleshooting

Due to added security and firewalls in Outlook, occasionally, an email creative may not load properly.

To troubleshoot Outlook issues in a test email, we will need a screenshot of the received test, the web browser, and the email platform.

Other recommended troubleshooting steps:

  • Test Emails: Send test emails to different email platforms (Gmail or others) and check if the images load correctly in each.
  • Check URLs: Ensure that the URLs of your images are accessible and correctly formatted.
  • Review HTML/CSS: Double-check your HTML code and CSS styles to ensure they are properly set up for email rendering.
  • Verify Hosting: Confirm that the images are hosted on a reliable server with proper permissions.

Outlook New

If a user is using Outlook New, there are known issues with viewing images in this version, and they have had to report the problem to Microsoft Engineering. This version is still in beta and not fully launched yet.

Red X On Images In Outlook

A red X box for images in Outlook typically means Outlook is configured to block automatic downloads of images from the internet to protect your privacy. You can unblock these images by adjusting your Outlook settings.

Here's how to fix it:

  1. Access Outlook Settings:

  • Outlook 2016, 2019, 2013, and 2010:

    • Go to "File" > "Options" > "Trust Center" > "Trust Center Settings" > "Automatic Download". 

  • Outlook 2007 and 2003:

    • Go to "Tools" > "Options" > "Security" > "Change Automatic Download Settings". 

  1. Modify Automatic Download Settings:

  • Clear the checkbox labeled "Don't download pictures automatically in HTML email messages or RSS items".

  • Click "OK" twice to save the changes. 

Additional Image Issues

There are several reasons why the images might not be loading in the user's Outlook.

Possible Causes & Solutions

  1. Image Hosting: If the images are hosted on a server that is not accessible or has restricted access, email platforms may not be able to display them. Ensure that the images are hosted on a public server or use a trusted image hosting service.

  2. Email Sent from an External Domain

Since the email is labeled [EXTERNAL], Outlook might be blocking the images due to security settings.
Solution:

  • Add the sender’s email address to Safe Senders List under Junk Email Options.

  • Go to File > Options > Trust Center > Trust Center Settings > Automatic Download, and check "Permit downloads from email addresses in my Safe Senders List."

  1. Older Version of Outlook Compatibility Issues

Older versions of Outlook (especially Outlook 2016 or earlier) handle HTML emails differently. Some emails use WebP images or advanced HTML/CSS that older Outlook versions struggle with.
Solution:

  • Check if the images are in WebP format—convert them to PNG or JPEG if needed.

  • Ensure the email is using inline images instead of referencing external URLs.

  1. Outlook Security Policies (Corporate IT Restrictions)

If the recipient is using a corporate or government email, IT policies might be blocking external images.
Solution:

  • Ask them to check with their IT team about image restrictions.

  • Try viewing the email in Outlook Web Access (OWA) to see if images load there.

  1. Cached or Corrupted Temporary Files

Sometimes, Outlook’s cache can cause images to not load properly.
Solution:

  • Clear Outlook’s cache:

    1. Close Outlook.

    2. Go to %localappdata%\Microsoft\Windows\INetCache\Content.Outlook\

    3. Delete the folder contents.

    4. Restart Outlook.

  1. Internet Connection Issues

If the recipient’s internet connection is slow or restricted, images may fail to download.
Solution:

  • Ensure they are connected to a reliable network.

  • Try viewing the email in a different email client or webmail.

Alt Text

This is a known issue in Outlook. During testing, we can attempt to mitigate it by shortening the alt text within the code.

However, alt text appears in the "Outlook New" version, which is still in beta and requires users to be on that version. In other versions, we see the alt text briefly appear before being replaced by Outlook’s default error message: "The linked image cannot be displayed..."

Further investigation shows that Outlook has several limitations with alt text. It primarily supports alt text for screen readers rather than displaying it visually in emails. As a result, alt text will be read aloud by screen readers but will not appear as visible text.

This issue is not commonly reported by our users, as most receive emails with images enabled. If images are disabled, users typically rely on screen readers, which will still read the alt text.

For creatives incorporating alt text, we recommend testing across multiple Outlook versions. This allows us to troubleshoot and adjust the text as needed to determine if specific modifications improve visibility or functionality.

  • FAQ: Is there a limit to how many characters we can use for the alt text to show? 
    • Usually, just a couple of words that describe the image is what alt-text is for. Normally, we put a sentence. There is no strict limit for it, but the longer it is the chances of it getting cut off.  We recommend trying to keep it under 100 characters and then testing to see if we need to shorten it more. 

Next Steps

  • Have the recipient try these troubleshooting steps.

  • Send a new test once the troubleshooting steps have been confirmed as completed.

  • If possible, test the email on another device or Outlook version to isolate the issue.

  • If corporate security policies are the issue, the IT department may need to whitelist the sender.