- Getting started
- Understanding UiPath Robot
- Installation requirements
- Installing robots for unattended automations
- Configuring robots for unattended automations
- Deploying unattended automations
- Connecting robots for unattended automations to Orchestrator
- Setting up Windows Server for High-Density Robots
- Redirecting robots through a proxy server
- Implementing authentication with credential providers
- Using network locations
- Setting up Linux robots
- Configuring package signature verification
- Setting up package folders and network paths
- Configuring activity feeds
- Installing robots for attended automations
- Configuring robots for attended automations
- Integrations
- Governance
- Troubleshooting

Robot admin guide
Execution troubleshooting
Automations that process large volumes of data may fail due to the following error: "Message: Could not retrieve the result of the job execution. This might be because a message was too large to process. Exception Type: System.Exception".
maxMessageSizeInMegabytes
parameter in the uipath.config
file.
Configure the automation to save the output in a Storage Bucket in Orchestrator or in Data Service, rather than using an output argument.
When a program such as Server Manager, set to start up automatically, shows a Windows User Account Control (UAC) prompt, it prevents the Robot from interacting with the user interface.
The Robot fails to start the execution of an automation and displays the following error: "Executor start process failed, reason System.Runtime.InteropServices.COMException: A specified logon session does not exist. It may already have been terminated.".
The following tables summarizes several issues and their solutions.
Potential issue |
Solution |
---|---|
The Robot machine does not have enough resources (such as CPU, RAM, or Disk Space), so the Robot Executor is unable to start the automation. |
|
The logon session cannot be created at the moment. This can happen in the following situations:
|
In this case, you need to perform one of the following:
|
Starting an automation from Orchestrator or Assistant displays the following error message: "Executor start process failed, reason System.UnauthorizedAccessException: Access is denied.".
The following table summarizes the potential issues and their solutions:
Potential issue |
Solution |
---|---|
The Robot account was created without a password. |
Edit the robot account in Orchestrator and provide the following values:
|
The Robot Service is inactive. |
|
The Robot machine no longer has administrator privileges. |
Log in to the Robot machine with the same set of credentials with which you created the Robot in Orchestrator. If a process fails to start from the Assistant, then you need to contact your network administrator to allow admin rights for that user account. |
When using a Data Table in a Wait For Task and Resume activity, it returns the following error: "Exception: Type 'System.Collections.IEnumerable' cannot be serialized."
The DataRow object of Data Table cannot be serialized, so it cannot be persisted, leading to potential issues or errors.
Execute the Create Form Task activity and build the output by looping through data rows, to create a list of task objects. Then, loop through the output list of task objects using the Parallel For Each or For Each activities. In these loops, execute the Wait for Task and Resume activity for each task object.
Your job execution fails and the following error message is logged in Orchestrator: "Job stopped with an unexpected exit code: 0x40010004".
Commonly, this error occurs when:
-
The user account, used by the Robot, is forcibly logged off during the execution of the process.
-
The machine on which the Robot is running is manually shut down or restarted during the process execution.
To avoid this error, make sure the Robot is installed correctly for the intended type of automation: attended or unattended. Having the Robot installed in User Mode cannot execute unattended automations.
Additionally, configure the Robot session to suit your environment and business needs.
The same automation works as expected in attended mode, with a human user logged in and watching, but in unattended mode it fails. Other potential issues in unattended mode include:
- The Robot clicks in incorrect locations.
- Random windows open unexpectedly.
- Items from the taskbar activate without user input.
- The target application enters an unexpected state.
For unattended automations, the Robot Service initializes the Windows session through an RDP connection and it relies on system settings for the display resolution and scaling, or on the Robot settings. Therefore, the resolution and scaling between the remote session and the local session is different.
Before testing, make sure the Robot user is logged out of the Robot machine. This way, the Robot operates in a clean environment.
Resolution differences are often the primary distinction between attended and unattended modes. Refer to Fixing resolution issues and Resolution best practices.
Possible solution |
Procedure |
Solution 1: Scaling settings check Scaling settings can affect how the Robot interacts with the user interface. |
If resolution fixes do not help with the issue, check the Windows session scaling settings:
|
Solution 2: Real-time problem capture |
If Solution 1 does not help, use the Live Streaming and remote control features to capture the issue as it occurs. These tools allow you to observe the Robot behavior without directly logging into the machine, helping identify issues that may not be apparent otherwise. |
Solution 3: UiPath support |
If the above steps do not help identify the issue, open a support ticket with UiPath. |
- Review the guidelines for UI Automations.
- Make resolution a key design requirement
- Ensure the resolution and scaling of your development and production environments are identical.
- Be aware that if you do not specify a resolution, system defaults apply. This may lead to low resolutions that the application does not support. UI elements may be offscreen or visually distorted.
- Do not overlook
resolution-dependent activities:
- Image-based activities, such as Find Image, or OCR activities.
- UI Automation activities with clipping regions enabled.
- UI Automation activities with the WaitVisible option enabled.
- Click activities that do not use Window Messages or Simulate input methods. For the CursorPosition property, refer to Robot clicking in the wrong location.
Incorrect Robot clicks typically indicate the CursorPosition option is enabled on the Click activity.
The CursorPosition property is sometimes configured unintentionally when using the Recording feature in Studio. Identify the activity where the click occurs in the wrong location, determine if the option is enabled intentionally. In most cases, this property is unnecessary.
- Log in to the machine as if running an attended automation.
- Open PowerShell (use the Run dialog and type "powershell").
- Execute this
command:
[void][Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms") [System.Windows.Forms.SystemInformation]::PrimaryMonitorSize
[void][Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms") [System.Windows.Forms.SystemInformation]::PrimaryMonitorSize - Write down the Width and Height values returned, as you need them in step 7b.
- Check font smoothing:
- Open View advanced system settings from the Start menu.
- On the Advanced tab, select Settings under Performance.
- Check if Smooth edges of screen fonts is enabled.
- If you need bit depth or font
smoothing, check display settings on the local machine that connects to the
Robot machine:
- Navigate to Display Settings.
- Go to Advanced display settings for bit depth information.
- Access the Robot Settings section for the robot
account executing the automation (Orchestrator >
Tenant > Manage Access > Access Rules >
Robot accounts).
- Set the Login To Console option to No. This instructs the Robot to use RDP sessions for unattended automations.
- Set values for Resolution Width and Resolution Height. Use the same values returned in step 3.
- Set 32 for Resolution Depth.
- For image-based automations, also set Font Smoothing to Yes.
- Select Update.
Optimally, redesign the automation in a development environment with scaling set to 100%. The following steps are intended as a temporary workaround. Make sure the Robot runs in an RDP session (the Login to Console option is set to No).
- Open the Registry Editor
and navigate to
HKEY_CURRENT_USER\Control Panel\Desktop\LogPixels
. - Search for the registry value
LogPixels
. If the value does not exit, create it as a32-DWORD
value. Consult the following list for possible decimal values:DPI (resolution)
Scale factor, % (the LogPixels value)
96
100 (no scaling)
120
125 (everything on the display is 25% larger)
144
150 (everything on the display is 50% larger)
192
200 (everything on the display is twice as large)
- Next, navigate to
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\
. - Search for the registry value
IgnoreClientDesktopScaleFactor
. This registry key tells the remote connection wheter to ignore the scaling on the Robot machine. If the value does not exit, create it as a32-DWORD
value. Consult the following list for possible decimal values:- 1 - ignores the scaling on the Robot machine
- 0 - takes into account the scaling on the Robot machine
- Message too large to process
- Description
- Potential issue
- Solution
- Unattended automations using UIAutomation activities do not work
- Description
- Potential issue
- Solution
- Robot fails to start execution
- Description
- Password not provided
- Description
- System.Collections.IEnumerable cannot be serialized
- Description
- Potential issue
- Solution
- Job stopped with an unexpected exit code
- Description
- Potential issue
- Solution
- Automation works in attended mode, but not in unattended mode
- Description
- Potential issue
- Solutions
- Resolution best practices
- Robot clicking in the wrong location
- Fixing resolution issues
- Forcing scaling