I have a project that includes a GUI executable that launches several background processes that communicate with each other to divide data processing. Recently, I copied the GUI to another machine and recompiled the background executables to test them.
However, when I tried to attach to the launched processes in Visual Studio, I couldn’t find them in the list of processes or in the task manager. Eventually, I discovered that the processes were running under “session 0”, which is an isolation mode in Windows 10, and I needed admin permissions to debug them.
I want to run these executables in my user session, so I need to understand what might have caused them to run in session 0.
What could prompt an executable to run at that level?
When a process runs in Session 0 in Windows 10, it means that it is running in an isolated session that is not accessible to regular users. This session is reserved for system services and is used to prevent malicious code from running with elevated privileges. However, there are situations where an executable may run in Session 0 unintentionally, which can cause problems for developers and IT administrators who need to manage these processes.
In this blog post, we will explore the common causes of processes running in Session 0 in Windows 10 and how you can avoid this problem in your own applications.
Using Windows Services
One of the most common reasons why an executable may run in Session 0 is when it is launched as a Windows service. Services are background processes that run automatically when the system starts up, and they are designed to run in Session 0 to ensure that they have the necessary permissions to perform system-level tasks.
If your application includes a service component, it will run in Session 0 by default. However, there are ways to configure the service to run in a user session instead. For example, you can use the “Interactive Services Detection” feature in Windows to allow the service to interact with the user desktop.
Using Task Scheduler
Another common way that an executable may run in Session 0 is when it is launched using the Task Scheduler. The Task Scheduler is a built-in Windows utility that allows you to schedule tasks to run automatically at specific times or events.
When you create a task in the Task Scheduler, you have the option to run it as a specific user or as the system account. If you choose to run the task as the system account, it will run in Session 0 by default. To avoid this, you can configure the task to run as a specific user instead.
Using Remote Desktop
If you are accessing a remote machine using Remote Desktop, any processes that you launch on that machine will run in Session 0. This is because Remote Desktop uses a separate session for each user that connects to the machine, and the first session (Session 0) is reserved for system services.
To avoid running processes in Session 0 when using Remote Desktop, you can use the “Remote Desktop Services” feature in Windows Server. This feature allows you to create multiple user sessions on a single machine, so you can run your applications in a separate session that is not reserved for system services.
Using the “Local System” Account
When you run an executable using the “Local System” account, it will run in Session 0 by default. This is because the “Local System” account is a highly privileged account that has access to all system resources, including those that are not accessible to regular users.
To avoid running processes in Session 0 when using the “Local System” account, you can create a separate user account with the necessary privileges and run the executable using that account instead.
Using the “Run as Administrator” Option
Finally, if you launch an executable using the “Run as administrator” option, it will run in Session 0 by default. This is because the “Run as administrator” option elevates the executable’s privileges to the highest level, which requires it to run in Session 0.
To avoid running processes in Session 0 when using the “Run as administrator” option, you can modify the executable’s manifest file to specify a lower level of privileges. This will allow the executable to run in a user session instead.
Running processes in Session 0 in Windows 10 can cause problems for developers and IT administrators who need to manage these processes. However, there are several ways to avoid this problem, including configuring services and tasks to run in user sessions, using Remote Desktop Services, creating separate user accounts with the necessary privileges, and modifying executable manifest files.
By understanding the common causes of processes running in Session 0 and how to avoid them, you can ensure that your applications run smoothly and securely on Windows 10.
There are a few potential reasons why your executable might be running in session 0 in Windows 10:
- The executable is configured to run as a Windows service, which runs in session 0 by default.
- The executable is launched by a service or another process running in session 0, and inherits the session of the parent process.
- The executable is launched from a shortcut or command prompt with the “Run as administrator” option, which causes it to run in session 0.
- The executable is launched from a scheduled task that is configured to run with the highest privileges, which also causes it to run in session 0.
It’s also possible that there could be other factors at play, such as group policy settings or security software that is intercepting the launch of the executable and redirecting it to run in session 0.
To determine the root cause of this behavior, you may need to do some further investigation. You can start by checking the properties of the executable and looking for any clues, such as a “Run as administrator” option or a service configuration. You can also check the scheduled tasks and services on the machine to see if any of them might be launching the executable.
To summarize, there are several possible reasons why an executable might be running in session 0 in Windows 10. These include being configured as a service, being launched by a process or service running in session 0, being launched with the “Run as administrator” option, or being launched from a scheduled task with the highest privileges.
To troubleshoot this issue, you can start by examining the properties of the executable and checking for any clues, such as a “Run as administrator” option or a service configuration. You can also check the scheduled tasks and services on the machine to see if any of them might be launching the executable.
If you continue to have difficulty determining the cause of this behavior, you may need to seek additional assistance. This could include reaching out to the developer of the executable, consulting online resources or forums, or seeking the help of a professional.
The following applications will run in session 0:
- System services that display a user interface
- System services that use API message functions like SendMessage and PostMessage to communicate with the user
- Applications that create global named objects
If your application is not running as a system service or creating such a service, it may be creating global named objects. These objects have names that are prefixed with “Global”. They are typically shared-memory segments or semaphores. You can view them by using WinObj in the “GLOBAL??” section.