Cannot communicate with the browser

The Cannot communicate with the browser, please check the UiPath extension error can indicate one of the following issues.

UiPath Extension for Edge is not installed or enabled

If you receive the Cannot communicate with the browser, please check the UiPath extension error message, the first step to take is to Check if the Extension for Microsoft Edge is installed and enabled.

Native Messaging Host (ChromeNativeMessaging.exe) is not running

Description

The native host must be running to enable the communication between the Robot and the UiPath Extension.

Solution

Use the following checklist to ensure the native host is running:

• Check if ChromeNativeMessaging.exe is running
• Check if ComSpec variable is defined correctly
• Check if the antivirus software blocks access to ChromeNativeMessaging.exe. To fix this issue, add the following folder to the antivirus allowlist:
  • C:\Program Files (x86)\Common Files\UiPath\UiPath.Common – if you're using Studio version 2023.10 and newer.
  • C:\ProgramData\UiPath\UiPath.Common – if you're using Studio versions older than 2023.10.

UiPath browser extension may fail to launch on slow machines with high CPU usage

Description

The browser extension can fail to initialize on slow machines with high CPU usage. This issue can have one of two causes:

• The Open Browser activity has an insufficient timeout.
• In some cases, this Chromium bug can cause the extension to fail to initialize and the browser must be restarted. This issue affects all browser extensions.

Solution

Increase the Open Browser timeout. You can find more details on how to do that in the Known issues specific to MV3 extensions page under the Open Browser activity has insufficient timeout section.

If you’ve increased the timeout and the issue persists, set to True the Enable retry setting introduced with UI Automation version 2023.10 in Project Settings > UI Automation Classic > Browser > Enable retry for OpenBrowser Edge.

When this setting is enabled, the Open Browser logic restarts the browser several times if the Native Host failed to initialize within the given timeout.

Extension gets corrupted because of Windows roaming profile

The browser extension may be corrupted due to a roaming user profile. For more information on roaming user profiles, see the Windows official documentation.

To solve this issue, see The extension may have been corrupted.