While Internet Explorer (IE) has been officially retired as a standalone browser, it remains integrated within Windows and may still influence Microsoft add-ins, especially on older or managed systems.
For modern Windows and Microsoft 365 environments, ExtendSync uses Microsoft Edge WebView2 as its embedded browser engine.
However, some legacy systems or older Outlook builds may still rely on Internet Explorer’s configuration.
⚠️ Note:
If you are on a modern Microsoft 365 or Outlook 2019+ build, these settings are typically not needed.
If you are on an older build or your IT department has not yet migrated your environment to WebView2, use the steps below.
Why Adjust Internet Explorer Settings
Even though you may not use Internet Explorer directly, it can still affect ExtendSync’s performance and authentication if:
You are running an older Windows build or Outlook version.
Group policies or user settings have modified IE’s security or caching configuration.
Cached data or blocked scripts are preventing ExtendSync from loading correctly.
CloudExtend apps generally perform well under default IE settings, but misconfigurations can cause add-ins to freeze, display a white screen, or fail authentication.
Configure Internet Explorer Settings
Follow these steps to restore IE’s default behavior and optimize performance for ExtendSync.
Step 1: Open Internet Explorer Settings
Close all Internet Explorer windows and all running programs on your machine.
Press the Windows Key + R on your keyboard to open the Run command prompt.
Enter inetcpl.cpl and click OK to open Internet Explorer Settings.
Step 2: Reset Internet Explorer
Select the Advanced tab.
Click Restore Advanced Settings, then click Reset.
Reset Internet Explorer Settings opens. Select Delete Personal Settings, then click Reset.
Click Close when complete.
Step 3: Clear Browsing History
Press Windows Key + R, type
inetcpl.cpl, and click OK again.Under the General tab, click Delete in the Browsing History section.
In the dialog that appears:
Deselect Preserve Favorites website data
Select:
Temporary Internet files and website files
Cookies and website data
History
Click Delete.
Under Temporary Internet Files and History Settings:
Select Every time I visit the webpage.
Set Disk space to use to 250 MB.
💡 If your organization uses Group Policy, check the Caches and Databases tab to ensure no cache limits are enforced.
Step 4: Add CloudExtend to Trusted Sites
Go to the Security tab → select Trusted Sites → click Sites.
In the Add this website to the zone field, enter:
https://*.cloudextend.ioClick Add, then click Close.
Step 5: Adjust Security Level
On the Security tab.
Click Trusted sites, then click Custom.
Under Security Settings - Trusted Sites Zone, complete the following actions:
In the Reset to: field, choose Low, then click Reset.
Click Yes on the warning dialog box.
Enable the following:
Websites in less privileged web content zone can navigate into this zone
Display mixed content
Initialize and script ActiveX controls not marked as safe for scripting
Click OK, then Yes when prompted.
Restart your computer.
Review your Internet Explorer settings and confirm that your new settings remain applied.
Depending on your permissions, changes may revert. If this occurs, contact your system administrator.
Step 6: Configure Privacy Settings
In Internet Explorer Settings, click the Privacy tab, then click Sites.
In the field that displays, enter
cloudextend.ioand click Allow.Click OK.
Then,click Advanced, configure the following:
Accept for both First-party cookies and Third-party cookies.
Always allow session cookies
Depending on your version of Internet Explorer, you may need to select Override automatic cookie handling to complete this step.
Click OK.
Step 7: Modify Advanced and LAN Settings
Go to the Advanced tab.
Enable: Allow active content to run in files on My Computer
Deselect: Check for server certificate revocation.
Go to Connections tab, then click LAN Settings.
Ensure that none of the boxes are selected.
If your network uses a proxy server, consult your IT help desk or system administrator. By default, the first box, Automatically detect settings, is selected.
If there are no proxy servers on your network, deselect this option.
Click OK.
Step 8: Restart and Verify
Close the Internet Explorer Settings window.
Re-open Internet Explorer. This completes the settings configuration process.
Modern Environment Note
If you’re running Microsoft 365 Apps for Windows, Outlook 2019, or newer:
Add-ins like ExtendSync now run using Microsoft Edge WebView2, not Internet Explorer.
IE settings only apply to legacy Windows or Outlook installations.
To ensure proper operation, confirm the WebView2 runtime is installed and up to date.