How to fix Gmail attachment errors

Matthew Adams
by Matthew Adams
Windows & Software Expert
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  • Gmail is one of the most popular web-based email clients in the world.
  • Unfortunately, users still receive the occasional error message when using attachments in Gmail.
  • To learn more about fixing common Gmail issues, go to our dedicated Gmail Fix Hub.
  • Thinking about switching from Gmail? Read more about alternatives on our Emails section.
fix Gmail attachment errors

Some Gmail users have found that the Attach files option in Gmail doesn’t always work.

Whenever they try to attach a file to an email, Gmail returns an error message stating:

Attachment failed. This may be due to a proxy or firewall

Consequently, they can’t attach files to emails. Here are a few potential fixes for the Attachment failed issue.


How do I fix Gmail attachment errors?

  1. Try third-party alternatives
  2. Grant Gmail permissions
  3. Update the Flash Plug-in
  4. Open Gmail in Another Browser
  5. Update the Browser
  6. Disable the Proxy Server
  7. Switch off Firewalls
  8. Adjust the Network.http.spdy.enabled Setting in Firefox

1. Try third-party alternatives

If you encounter errors when trying to use attachments on Gmail, the best workaround is to use Mailbird – Winner of Most Popular Mail Alternative 2020.

This incredible user-friendly and easy-to-use software offers you a wide range of capabilities that include everything Gmail has to offer, minus the attachment errors.

With MailBird you will always be able to access your attachments, and even more, you can easily find a specific attachment by using the Advanced Attachment Search function.

This feature gives you the ability to use search terms to identify which emails contain attachments, search by size, minimum pixel size, and also by thumbnail size.

Don’t miss out on this amazing software to ensure that your attachments will always be easily accessible with just a few clicks of the mouse.

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2. Grant Gmail permissions

The first thing to do and which might be causing the problem with the attachments are browser extensions and permissions.

That’s why we encourage you to disable all browser extensions temporarily (the focus is on adblockers) and check whether Gmail web-client has all permissions.

Just click on the padlock icon in the Address bar and make sure Gmail has access to your emails. That should be enough to resolve the error. In case it isn’t, continue with the steps below.


We’ve written about Gmail attachment errors before. Bookmark this page in case you need it.


3. Update the Flash Plug-in

  1. First, open this page that lists the latest Flash versions.
  2. Open this website page if you don’t have the latest Flash version listed on the Adobe Flash Player page.
  3. Deselect the optional offers check boxes if you don’t need the extra software.adobe flash player install
  4. Then press the Install Now button to save the Flash Player installer.
  5. Open the Adobe Flash Player Installer window shown directly below to install Flash.update flash player preferences
  6. Thereafter, check that Flash is enabled in your browser.
  7. You can do that in Chrome by clicking the Customize Google Chrome button and selecting Settings.
  8. Scroll down the Settings page, and click Advanced to expand the options.
  9. Click Settings and select Flash to open the options shown directly below.enable flash in chrome
  10. Select the Allow sites to run Flash option.

Gmail’s default attachment uploader utilizes Flash. The attachment uploader might not work with antiquated Flash versions.


4. Open Gmail in another browser

You might find that Gmail‘s file attachment works fine in an alternative browser. As such, open Gmail in another browser; and then attach a file to an email.

Note that Gmail only supports Chrome, Firefox, Safari, Internet Explorer and Edge browsers.


You can also try UR browser, the safest browser for surfing the web. Read our review!


5. Update the Browser

  1. Click the Customize Google Chrome button to open the browser’s main menu,
  2. Select Help > About Google Chrome to open the tab shown directly below.update google chrome
  3. The browser will automatically download any available updates.
  4. Then click Relaunch to restart the browser.

You should also check for browser updates to ensure you’re using the latest version. Gmail attachment errors are more likely to occur in outdated browsers.


6. Disable the Proxy Server

  1. Click the Cortana button on the Windows 10 taskbar, and enter ‘internet options’ in the search box.
  2. Select Internet Options to open the window directly below.internet options
  3. Click the Connections tab in the snapshot below.internet options connections
  4. Press the LAN settings button.LAN settings Internet options
  5. Deselect the Use a proxy server for your LAN setting, and press the OK button.

The Attachment failed error message states that the issue could be due to a proxy server. As such, switching the web browser proxy off, if selected, might fix the error.


The proxy can’t be disabled no matter what you do? Here’s a guide just for such an occasion.


7. Switch off Firewalls

  1. Open Run by pressing the Win key + R hotkey.
  2. Enter ‘firewall.cpl’ in the Open text box, and press the OK button.firewall.cpl run
  3. Click Turn Windows Firewall on or off to open the settings shown directly below.firewall settings for each type of network
  4. Select both the Turn off Windows Firewall options on the Customize Settings tab.
  5. Press the OK button to close the tab.
  6. Your third-party anti-virus software might also have its own firewall. You can switch a third-party firewall off by right-clicking the anti-virus software’s notification area icon and selecting its disable or turn off the option.

The Attachment failed error message also hints that a firewall might be responsible for the issue.

To ensure there’s no firewall interference for email attachments, you can temporarily switch them off.


8. Adjust the Network.http.spdy.enabled Setting in Firefox

  1. Enter about:config in Firefox‘s URL bar to open the tab shown directly below.firefox advanced configuration
  2. Next, input Network.http.spdy.enabled in the search box at the top of the about:config page.
  3. Then double-click the Network.http.spdy.enabled setting to switch its value to false.network advanced configuration firefox
  4. Close Firefox and restart the browser.

This resolution is more specifically for Firefox users. Switching the Network.http.spdy.enabled setting to false can resolve the Attachment failed issue.

Those resolutions will probably fix the Attachment failed error so that you can attach files to Gmail emails again.

However, you can also report the issue to Google with the Gmail support contact form if further fixes are required.


Editor’s Note: This post was originally published in April 2019 and has been since revamped and updated in September 2020 for freshness, accuracy, and comprehensiveness.

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