Overview
If you attempt to start the Code42 agent and it displays the message, "Code42 cannot connect to its background service", this article can help troubleshoot the issue. This error usually occurs because the Code42 service is not running.
However, if you see "Unable to connect, check your network" or "Can't connect to server", that indicates a network issue. Network issues occur when the Code42 agent cannot communicate with the Internet. To fix a network issue, check that there is no software that conflicts with the Code42 agent installed on your system and see Test your network connection to further troubleshoot the issue.
Under the hood
The Code42 agent consists of two parts:
- Graphical user interface that the user interacts with
- Code42 service that runs in the background
These two pieces communicate over a local network connection that is built into every device. When the Code42 agent starts, the graphical user interface and the Code42 service attempt to connect to each other. If they can't connect, the graphical user interface displays an error message.
To learn more about Code42 agent status messages, see Code42 agent status messages.

Recommended solutions (all operating systems)
The recommendations below apply to all operating systems. These are the resolutions that most often resolve the issue. If these solutions don't resolve the issue, review additional recommendations below.
Restart the Code42 service
The first thing to try on all platforms is to restart the Code42 service. If this doesn't resolve the issue, try the recommended solutions below.
Out of memory
If you have a large backup selection (more than 1 TB or 1 million files), you may need to allocate more memory to the Code42 agent. When the Code42 agent runs into this memory limit, the Code42 service is not able to run, resulting in the "Code42 cannot connect to its background service" message. If you have a large file selection backing up, refer to our troubleshooting article on this topic to address the issue.
Remove Code42 agent files from previous installations
If the Code42 agent was previously installed per user, uninstalling and reinstalling for everyone (the default installation) causes an error. To resolve this issue, complete the following steps:
- Locate the .ui_info file from the previous per-user installation:
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Windows: C:\Users\<username>\AppData\<Local or Roaming>\CrashPlan
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Mac: /Users/<username>/Library/Application Support/CrashPlan
On Mac, the .ui_info file is hidden by default. See Lifewire's tutorial to show hidden files to view the .ui_info file.
- Delete the .ui_info file.
Deleting this file does not harm your backup. It is a file left over from a previous installation and it is no longer necessary.
- Restart the Code42 agent notification area or menu bar app:
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Windows: From the Windows Start menu, select Code42 > Code42 Tray.
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Mac: Open the Code42 agent and select Settings > Show Code42 status in menu bar.
Confirm the user detection script detected a valid user
If your user detection script is unable to detect a valid user, the Code42 agent may display the message "Unable to connect to the background service" or "Code42 cannot connect to the background service." To determine if the script is the cause of this issue, check the user detection log on the device:
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Windows: \ProgramData\CrashPlan\log\userDetect_Result.log
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Mac: /Library/Logs/CrashPlan/userDetect_Result.log
If the log indicates no valid user was detected, review your user detection script. For assistance troubleshooting, contact our Technical Support Engineers.
Recommended solution (Windows)
If you are using a Windows device and the recommended solutions for all operating systems didn't resolve the problem, verify that the Code42 service is enabled.
- Open the Windows Start menu.
- Locate and open the Services program: Type services.msc into the Start menu search bar and click Enter.
- Double-click Code42 Service.
The Code42 Service Properties window opens.
- Ensure that the Startup Type is set to Automatic (Delayed Start).
- If the Start service status button is available, click it to start the Code42 service.
- Click Apply if you made changes to your settings, then close the window.
Recommended solution (Linux)
If your system language is not set to English when the Code42 agent is installed, the application starts and backs up but fails to open after rebooting the device. To ensure that the Code42 agent is able to open after rebooting:
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Uninstall the Code42 agent.
- Change the Linux system language to English.
Consult the documentation for your Linux distribution for instructions on changing the system language.
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Install the Code42 agent.
- Change the Linux system language back to your language.
The Code42 agent will open normally.
Alternative solution
Manually starting the Code42 service after restarting your device will allow you to open the Code42 agent.
Starting the Code42 service
Using this method to start the Code42 service will not persist after restarting the device and will have to be reapplied after every restart.