Error "Open browser: Can not communicate with Internet Explorer browser."

How to troubleshoot when using Open Browser activity, the following error is generated: "Open browser: Can not communicate with Internet Explorer browser." ?

When using an “Open Browser” activity the following error is generated:
         “Cannot communicate with Internet Explorer browser.”
                         

This error can occur for a few reasons. The following steps can be used to diagnose and find the root cause of the exception.


Diagnosing the Issue

  • If this issue is intermittent then go to the Troubleshooting Intermittent Browser Communication Issues section.
  • If the error was encountered upgrading to 18.3 or above, please go to the Fixing Application Packages Permission section.
  •  If using UiAutomation package 19.4.+ and the the first page that IE opens is a page requiring a user to enter their username and password in a windows security prompt (see below), go to the Handling Login Screen section. 
  • Check the configuration settings of Internet Explorer.
    <ul><li style="margin-bottom: 11px;"><span style="font-size: 14px;" uipath_custom_id="50"><span style="line-height: 107%;" uipath_custom_id="51"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="52"><span style="line-height: 107%;" uipath_custom_id="53"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="54">Open “run” and type “inetcpl.cpl” to bring up the IE settings page.</span></span></span></span></span></li></ul>
    </li></ul>
    

                            

      • Go to the “Advanced” tab.
      • Check to see if either of the Enhanced Protected Mode settings are enabled.
                                         
      • If either of these settings are enabled, then go to the Fixing Application Packages Permission section.
    • If none of the above solutions have helped, please go to the section on System Misconfiguration.

    Intermittent Browser Connection Issues

    These are the following conditions under which the “Cannot Communicate with browser” issue can occur intermittently.
    1. This error is only generated when using the “Open Browser” Activity.
    2. Internet Explorer takes too long to start.
    3. Internet Explorer starts, but the page it opens to, takes too long to load.
    The typical scenario where this situation will occur is when the CPU load is too high as Internet Explorer is known for having poor performance under such conditions. In this situation, certain timeouts in the Robot activities will be reached and generate the “Cannot Communicate with browser exception”. (these timeouts cannot be controlled by the user)
    To verify that CPU usage is the issue, try the following steps:
    1. Check the CPU usage at logon time. At logon time, the CPU usage can be especially high due to logon scripts or programs.
      <ul style="list-style-type: square;"><li><span style="font-size: 14px;" uipath_custom_id="119"><span style="line-height: 107%;" uipath_custom_id="120"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="121"><span style="line-height: 107%;" uipath_custom_id="122"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="123">Logon to the machine and then logout (do not disconnect!). This step is to ensure that the computer does all its logon operations.</span></span></span></span></span></li><li><span style="font-size: 14px;" uipath_custom_id="124"><span style="line-height: 107%;" uipath_custom_id="125"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="126"><span style="line-height: 107%;" uipath_custom_id="127"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="128">Log back into the machine and immediately open task manager.</span></span></span></span></span></li><li><span style="font-size: 14px;" uipath_custom_id="129"><span style="line-height: 107%;" uipath_custom_id="130"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="131"><span style="line-height: 107%;" uipath_custom_id="132"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="133">If CPU is high, then consult with your system admin to determine what is causing the spike in CPU usage.</span></span></span></span></span></li><li><span style="font-size: 14px;" uipath_custom_id="134"><span style="line-height: 107%;" uipath_custom_id="135"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="136"><span style="line-height: 107%;" uipath_custom_id="137"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="138">You may have to immediately try starting the Robot from the Robot tray after logging in.</span></span></span></span></span></li><li><span style="font-size: 14px;" uipath_custom_id="139"><span style="line-height: 107%;" uipath_custom_id="140"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="141"><b><span style="line-height: 107%;" uipath_custom_id="142"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="143">As a workaround, you can try adding a delay to the automation so that it waits to run until after CPU usage has decreased. You can also try a retry mechanism.</span></span></b></span></span></span></li></ul>
      </li><li><span style="font-size: 14px;" uipath_custom_id="144"><span style="line-height: 107%;" uipath_custom_id="145"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="146"><span style="line-height: 107%;" uipath_custom_id="147"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="148">Watch the automation run.</span></span></span></span></span>
      <ul style="list-style-type: square;"><li><span style="font-size: 14px;" uipath_custom_id="149"><span style="line-height: 107%;" uipath_custom_id="150"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="151"><span style="line-height: 107%;" uipath_custom_id="152"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="153">Logon to the machine.</span></span></span></span></span></li><li><span style="font-size: 14px;" uipath_custom_id="154"><span style="line-height: 107%;" uipath_custom_id="155"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="156"><span style="line-height: 107%;" uipath_custom_id="157"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="158">Open Task Manager.</span></span></span></span></span></li><li><span style="font-size: 14px;" uipath_custom_id="159"><span style="line-height: 107%;" uipath_custom_id="160"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="161"><span style="line-height: 107%;" uipath_custom_id="162"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="163">Start the automation once CPU usage is low.</span></span></span></span></span></li><li><span style="font-size: 14px;" uipath_custom_id="164"><span style="line-height: 107%;" uipath_custom_id="165"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="166"><span style="line-height: 107%;" uipath_custom_id="167"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="168">See if the CPU spikes when the automation is running.</span></span></span></span></span></li><li><span style="font-size: 14px;" uipath_custom_id="169"><span style="line-height: 107%;" uipath_custom_id="170"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="171"><span style="line-height: 107%;" uipath_custom_id="172"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="173">If CPU usage is high while the automation is running, try to minimize how many browser tabs get open at one time and try to reduce the number of applications running in the background.</span></span></span></span></span></li></ul>
      </li><li><span style="font-size: 14px;" uipath_custom_id="174"><span style="line-height: 107%;" uipath_custom_id="175"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="176"><span style="line-height: 107%;" uipath_custom_id="177"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="178">Consider using Procmon to monitor the computer while the process is running.</span></span></span></span></span>
      <ul style="list-style-type: square;"><li><span style="font-size: 14px;" uipath_custom_id="179"><span style="line-height: 107%;" uipath_custom_id="180"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="181"><span style="line-height: 107%;" uipath_custom_id="182"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="183"><a href="https://docs.microsoft.com/en-us/sysinternals/downloads/procmon" style="color: blue;text-decoration: underline;" target="_blank">https://docs.microsoft.com/en-us/sysinternals/downloads/procmon</a></span></span></span></span></span></li></ul>
      </li><li><span style="font-size: 14px;" uipath_custom_id="184"><span style="line-height: 107%;" uipath_custom_id="185"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="186"><span style="line-height: 107%;" uipath_custom_id="187"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="188">Generate an ETL file and open a support request.</span></span></span></span></span>
      <ul style="list-style-type: square;"><li><span style="font-size: 14px;" uipath_custom_id="189"><span style="line-height: 107%;" uipath_custom_id="190"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="191"><span style="line-height: 107%;" uipath_custom_id="192"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="193">Follow the instructions for generating diagnostic logs: <a href="https://docs.uipath.com/robot/docs/robot-logs#section-enabling-robot-diagnostic-logs" style="color: blue;text-decoration: underline;" target="_blank">https://docs.uipath.com/robot/docs/robot-logs#section-enabling-robot-diagnostic-logs</a></span></span></span></span></span></li><li style="margin-bottom: 11px;"><span style="font-size: 14px;" uipath_custom_id="194"><span style="line-height: 107%;" uipath_custom_id="195"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="196"><span style="line-height: 107%;" uipath_custom_id="197"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="198">Open a support request and include the generated ETL file. (You need a special application to read the file.)</span></span></span></span></span></li></ul>
      </li></ol>
      


      If any of these tests show that CPU usage is high, please see below for best practices and work arounds. Also consider working with your IT team to resolve the issue.


      Fixing Application Packages Permission

      When running Internet Explorer in Enhanced Protected Mode, any application or its components have to a special permission in order to interact with Internet Explorer.
      Prior to 18.3 UiPath packages had this permission by default, however after 18.3 some packages were moved to %userprofile%/.nuget and no longer have the special permission.

      1. Logon to the account running the automation.
      2. Open file explorer and go to %userprofile%/.nuget (%userprofile% is a variable that resolves to the current user’s home directory).
                     
      1. Right click the “packages” folder and select “properties”.
      2. Go to the Security tab and select “Edit”.
                     
      1. Next Select “Add”
                     
      1. In the “Select Users or Groups” dialog box, type in the object as “All Application Packages”. After typing it in, click “Check Names” and then “OK”.
                     
      1. After adding the group, make sure that it has the following permissions:
        <ul style="list-style-type: square;"><li><span style="font-size: 14px;" uipath_custom_id="263"><span style="line-height: 107%;" uipath_custom_id="264"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="265"><span style="line-height: 107%;" uipath_custom_id="266"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="267">Read &amp; execute</span></span></span></span></span></li><li><span style="font-size: 14px;" uipath_custom_id="268"><span style="line-height: 107%;" uipath_custom_id="269"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="270"><span style="line-height: 107%;" uipath_custom_id="271"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="272">List folder contents</span></span></span></span></span></li><li><span style="font-size: 14px;" uipath_custom_id="273"><span style="line-height: 107%;" uipath_custom_id="274"><span style="font-family: Calibri,sans-serif;" uipath_custom_id="275"><span style="line-height: 107%;" uipath_custom_id="276"><span style="font-family: &quot;Arial&quot;,sans-serif;" uipath_custom_id="277">Read</span></span></span></span></span></li></ul>
        </li></ol>
        

                              

        1. After making this change, check to see if the error still occurs. If does check the section on System Misconfiguration.


        System Misconfiguration

        These problems can be very difficult to diagnose because they do not always generate system errors that can be used to find the misconfiguration. But there are some configurations settings we can reset to solve these issues.
        1. Sometimes after a Windows Update certain .dll files can become unregistered and cause issues with automations that interact with Internet Explorer.
        The easiest way to verify these files are registered are just to re-register them by using regsvr32.
        More info can also be found at: https://docs.uipath.com/studio/docs/identifying-ui-elements-after-windows-updates
        • These series of commands will make sure the correct dll files are registered and are perfectly safe to run.
        • Open an elevated Command Prompt.
        • Run the following series of commands:
          • regsvr32 C:\Windows\System32\oleacc.dll
          • regsvr32 C:\Windows\System32\oleaut32.dll
          • regsvr32 C:\Windows\SysWOW64\oleacc.dll
          • regsvr32 C:\Windows\SysWOW64\oleaut32.dll
        1. <span style="font-