How to fix Gmail attachment errors

Matthew Adams
by Matthew Adams
Windows & Software Expert
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Some Gmail users have found that the Attach files option in Gmail doesn’t always work.

Whenever they try to attach a file to 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.

Gmail attachment error: 7 solutions to fix it

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

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

1. 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.

2. Update the Flash Plug-in

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

As such, check that you have the latest Flash version as follows.

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

3. 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 the Chrome, Firefox, Safari, Internet Explorer and Edge browsers.

Alternatively, you can try UR browser, the safest browser for surfing the web. Read our review to learn more!

4. Update 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.

You can update Google Chrome as follows.

  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.

5. Disable the Proxy Server

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.

This is how you can 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.

Sometimes, the proxy can’t be disabled no matter what you do. We’ve prepared a simple guide just for such an occasion.

6. Switch off Firewalls

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. This is how you can disable the Windows Firewall.

  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 option.

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

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

You can adjust that setting in about:config as follows.

  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 advanced configuration firefox
  4. Close Firefox and restart the browser.

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 October 2017 and has been since completely revamped and updated for freshness, accuracy, and comprehensiveness.


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