Process Lasso Troubleshooting: Fixes for Common Errors and Startup Popups

Most Process Lasso problems come down to a few causes: A process that Windows or an anti-cheat system protects, a core engine that was stopped, or a startup setting. This page covers each common error message and popup, what causes it, and how to fix it. Before you start, make sure you are running the latest release, since many issues are fixed in newer versions.

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“Access is denied” When Setting CPU Priority

Process Lasso shows “Access is denied.” when Windows refuses to let it change a process. This happens with protected system processes, some security software, and games protected by anti-cheat systems. It is a Windows restriction, not a fault in Process Lasso, and it applies to I/O, memory and GPU priority too.

Make sure Process Lasso is elevated. If Main / Elevate Now is available, choose it. Without administrator rights, Process Lasso can only change your own processes.
Use a registry-enforced rule. Right-click the process and choose CPU Priority / Always / Enforce by Windows Registry. Windows itself then applies the priority each time the process starts, so it works even on protected processes. Restart the program for it to take effect. When an Always rule fails, Process Lasso offers this automatically. The same option exists under I/O Priority and Memory Priority.
For games with anti-cheat, see Working with anti-cheat systems.

To review or remove registry-enforced rules, use Options / General / View Priorities Saved to Registry. Raising a program to High or Realtime priority rarely helps, so before working around an error, check whether you need the change at all.

“WARNING: The core engine is not running!”

The core engine (processgovernor.exe) is the part of Process Lasso that applies your rules and ProBalance. It runs in the background, separately from the window you see, so rules keep working when the window is closed. When it stops, Process Lasso shows this warning in the tray icon tooltip and on the graph, and rules stop being applied.

To start it again, choose Main / Start or Stop Core Engine (Governor), or the same item on the tray icon menu. It is shown as Start Governor while the core engine is stopped.

If it keeps stopping, check these causes:

It was stopped when the window was closed. When you exit Process Lasso, it asks whether to also stop the core engine. If you answered Yes and chose Do not ask again, it stops every time. Use View / Reset / Reset ‘Do Not Show Again’ Memory to get the question back, and answer No.
It is set to start only with the window. Open Options / General / Configure Startup… and under Core Engine (Governor) Startup, choose Start core engine as a service at system boot, the default and recommended setting.
Security software is blocking it. Allow ProcessLasso.exe and ProcessGovernor.exe in your antivirus or behavior-blocking software.
The service is pending deletion. If Process Lasso says the ProcessGovernor service is marked as pending delete, restart your PC.
Task Scheduler is disabled. Process Lasso uses Windows Task Scheduler to start at login. If it warns that Task Scheduler is unavailable, re-enable the Task Scheduler service.

“ERROR setting process CPU affinity”

This log entry means Windows refused a CPU affinity change, or the process exited before it could be applied. Changing affinity from the right-click menu shows “Access is denied.” for the same reasons as priority: Protected processes, security software and anti-cheat systems. To fix it:

Use CPU Sets instead. Right-click the process and choose CPU Sets / Always. CPU Sets are a softer, Windows-native way to prefer certain cores, and they work in more cases. See CPU Sets.
Set the rule on the launcher. A process inherits its CPU affinity from the program that starts it. If a game blocks changes, set a CPU Affinity / Always rule on its launcher instead, and the game starts with the same cores. The setup guide shows this for Escape from Tarkov.
On PCs with more than 64 logical CPUs, Windows limits affinity for processes that span processor groups. Use a persistent CPU Affinity / Always rule, which Process Lasso keeps reapplying, or CPU Sets.

To see these errors, turn on Options / Log / Log Affinity Adjustments, then open View / View Log….

A few different windows can appear when Process Lasso starts:

The free version reminder. The free version shows a short reminder at startup, with a brief countdown before you can continue. Activating a Process Lasso Pro license removes it for good. You can also activate from the reminder itself with Activate my license.
The main window opening at login. Process Lasso normally starts hidden in the tray. To keep it from starting at all, open Options / General / Configure Startup… and under Management Console (GUI) Startup, choose Do not start at login. Your rules and ProBalance keep working, because the core engine runs on its own.
A User Account Control (UAC) prompt. Process Lasso starts at login through Windows Task Scheduler with full rights, so it does not normally ask for permission. If you see a UAC prompt at every login, the startup task is missing: Open Options / General / Configure Startup… and save your startup choice again.
“The Process Lasso configuration is not writable.” See this FAQ entry, or, on Remote Desktop servers, this one.
“Update Available!” This tray notice appears when a new version is out. Change how often Process Lasso checks under Updates / Check Every….

My Rules Don’t Seem to Stay in Effect

Some programs change their own priority or affinity after Process Lasso applies a rule. Turn on Options / Forced Mode to have Process Lasso keep reapplying your rules. See Forced Mode in the FAQ.

Activation Problems

If activation fails, see activation errors. If you have to re-enter your code at every startup, see this FAQ entry.

Still Stuck?

Search the Process Lasso FAQ, ask on the community forum, or contact us. The log at View / View Log… shows what Process Lasso has done and is the most useful thing to include when you ask for help.