Our corporate BOFH imposes the screen lock setting with a ridiculously short delay. It's frustrating and counterproductive.

Is there a way to prevent the automatic screen lock? I would assume there is no way to override the policy-enforced setting, but maybe there is a software that mimics user activity.

Just asking before I set up a perpetual mouse wheel. (get it?)

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    Just curious what "ridiculously short" is? – Carl Aug 30 '11 at 15:45
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    15 minutes. OK, it's not that short ... unless you are at home, not in an open space, and also often working on a second computer. Like I am, so the screen lock is obnoxious. – Gabriel R. Aug 31 '11 at 10:32
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    The grace period doesn't work for me, while the script does. I assume that my corporate policy also disables the grace period. – Dane Jacob Hampton Apr 20 '18 at 8:41
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    Late to the game here, but wanted to add my solution. Since I don't have admin rights to the PC I use at work, and none of the scripts or programs in this thread worked for me (either they weren't allowed to be installed, or just didn't work), I purchased a "USB Mouse Jiggle" hardware from Amazon. Works like a dream, only $15. – Jeff Wright Apr 30 '18 at 11:01
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    My previous company has a 2-minute screen lock policy. That's not ridiculous but disaster and torturous and sometimes depressing. – Lame User Dec 27 '19 at 8:07

13 Answers 13


Yet another option is freeware Caffeine program. It is free for commercial use as well. From the program's homepage:

If you have problems with your PC locking or going to sleep, caffeine will keep it awake. It works by simulating a key-press once every 59 seconds, so your machine thinks you're still working at the keyboard, so won't lock the screen or activate the screensaver.

Caffeine works by simulating an F15 key up event every 59 seconds. Of all the key presses available, F15 is probably the least intrusive (I've never seen a PC keyboard with that key!), and least likely to interfere with your work.

This off-the-shelf solution also allows you to control when to enable it and disable it:

Double-clicking the program icon empties the coffee pot, which is what the icon represents, and temporarily disables the program. Double-clicking it again refills the pot, and will keep your machine awake.

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    I'm waiting for the day when a Gov't employee puts Caffeine on their computer and it just so happens that something like Shift+F15 launches the nukes... – kazoni Jun 24 '15 at 17:37
  • Nice easy "off the shelf" solution, thanks. Seems to have about as many command-line options as gcc, but I don't need to use any of them! – Sam Watkins Aug 4 '16 at 3:07
  • The tool works great for me! I had to install the Visual C++ 2008 Redistributable to get it working. microsoft.com/en-us/download/details.aspx?id=26368 – Synck Oct 2 '19 at 7:07
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    I think in a corporate environment you could (and should) get into trouble for installing such a tool on a machine, especially if it's not 'your' machine. The VBS solution is much cleaner, at least you know exactly WHAT it does. – Bartosz Jul 23 at 9:14

If Windows Media Player is still installed, you can play a video on loop and minimize it (the sample "Wildlife" videos work fine for this). By default, as long as a video is playing, the screen won't lock.

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    Thank you! This is the simplest, most effective solution. (I didn't try it though, I left the company a while ago and try to stay away from Windows.) – Gabriel R. Apr 16 '13 at 11:43
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    I confirm that this works on Windows XP using an MP3 file instead of a video. – Alaa Ali Sep 23 '13 at 9:59
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    Brilliant hack! – user42225 Apr 2 '14 at 13:51
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    This also works using VLC for those who prefer it over Windows Media Player – ecoe May 5 '14 at 15:22
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    Works fine in Windows 7. Nice hack! – neves Nov 5 '16 at 1:52

I use a script I title idle.vbs:

Dim objResult

Set objShell = WScript.CreateObject("WScript.Shell")    

Do While True
  objResult = objShell.sendkeys("{NUMLOCK}{NUMLOCK}")
  Wscript.Sleep (6000)

Every six seconds, this quickly toggles numlock on the keyboard, causing Windows to believe that someone is interacting with the keyboard, preventing screen lock. This runs on vanilla windows, you don't need development or scripting tools to use it, just make a text file with .vbs as the extension and double-click it (or place it in your startup items).

Edit: you can put this script in your startup items with

 choco install IdleVbs -source https://www.myget.org/F/joshrivers-utility/

For more information on the Choclatey (choco) CLI installer please see:


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    @JoshRivers a way to stop this script, without having to restart the computer, would be nice as well. – DeeJayh Feb 3 '17 at 17:52
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    @DeeJayh I think you can just find the instance of wscript.exe in Task Manager and kill it. There usually aren't a lot of instances of that executable running. You could probably make an automated solution for termination (stackoverflow.com/a/22325745) or by putting code in the Do While section that watches for an external fact. Like have the script create a file on startup, then check that the file exists in While. That way you could just delete the file to make the script terminate. (I never quit the thing, though, so I just run the script and very rarely kill it with Task Manager). – JoshRivers Feb 4 '17 at 20:28
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    On Windows 10, an easy way to locate the startup folder is display the Start->Run window (e.g. WindowsKey+R) and then type shell:startup. See this site for more info thewindowsclub.com/startup-folder-in-windows-8 – buzz3791 Apr 12 '18 at 15:55
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    To find the script look for Microsoft Windows Based Script Host in your task manager. Or add a column Process Name and then look for wscript.exe. – JohnAndrews Jun 6 '18 at 8:30
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    Works great on a Win10 Surface laptop - that does not even have a physical NumLock key! – Shahar Dec 19 '18 at 15:45

You can create an AutoIt script to either continually press an unused key (e.g. make it toggle the num lock, scroll lock), sleep for a minute or so, and repeat. Alternatively, if you use the keyboard a lot, you could make it move the mouse by a pixel or so in any direction.

If you don't want it continually running, you could also launch the script as a scheduled task (if you have access) to launch after the computer has been inactive for some time.

And this is a very simple script to perform an invisible mouse move, if you don't want to get into AutoIt syntax:

While True
   Local $pos = MouseGetPos()
   MouseMove($pos[0]-1, $pos[1]-1, 0)
   MouseMove($pos[0], $pos[1], 0)

This script moves mouse cursor by one pixel in the up-left direction and after that returns it back, then sleeps for 9 minutes (540000 milliseconds). When script is running, you can see AutoIt icon in the tray. You can stop it right-clicking this icon and choosing the corresponding option.

To make a script, install AutoIt, right-click in any folder and choose New > AutoIt v3 Script, name it, right-click this new script, choose Edit, paste the code provided above and save. You can even compile it to .exe (again, from context menu) to start, for example, from Windows Scheduler.

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There is an android app called "Timeout Blocker" that vibrates at an interval and you can put your mouse on it. It says not to use it at work though. https://play.google.com/store/apps/details?id=com.isomerprogramming.application.timeoutblocker&hl=en

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Compile this in Visual Studio or C# Express and run it from a command prompt (or double click it). Requires .NET 4.0 or above. It does everything you are looking for.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Threading;
using System.Runtime.InteropServices;
using System.Windows.Forms; 

namespace ImWorkin
    class Program
        public enum EXECUTION_STATE : uint
            ES_SYSTEM_REQUIRED = 0x00000001,
            ES_DISPLAY_REQUIRED = 0x00000002,
            ES_CONTINUOUS = 0x80000000
        public SYSTEMTIMEOUTS TimeOuts
            get { return sysTimeouts; }
        public struct SYSTEMTIMEOUTS
            public int BATTERYIDLETIMEOUT;
            public int EXTERNALIDLETIMEOUT;
            public int WAKEUPIDLETIMEOUT;

        [DllImport("USER32.DLL", CharSet = CharSet.Unicode)]
        public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        public static extern bool SetForegroundWindow(IntPtr hWnd);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern EXECUTION_STATE SetThreadExecutionState(EXECUTION_STATE flags);

        [DllImport("user32.dll", SetLastError = true, EntryPoint ="SystemParametersInfo")]
        internal static extern int SystemParametersInfo(int uiAction, int uiParam, ref int pvParam, int fWinIni);

        private static System.Threading.Timer preventSleepTimer = null;
        public const int SPI_GETBATTERYIDLETIMEOUT = 252;
        public const int SPI_GETEXTERNALIDLETIMEOUT = 254;
        public const int SPI_GETWAKEUPIDLETIMEOUT = 256;
        public static int Counter = 0;
        public static int timeOutinMS = 0;
        public static int batteryIdleTimer;
        public static int externalIdleTimer;
        public static int wakeupIdleTimer;
        public static SYSTEMTIMEOUTS sysTimeouts;

        static void Main(string[] args)
            Console.WriteLine("You are about to be workin!! Just a moment...I need to calculate a few values.");
            string dots = string.Empty;
            for (int i =2; i < 60; i++)
                dots = "";
                for (int ii = 0; ii < i; ii++)
                    dots = dots + ".";
                Console.WriteLine("You are about to be workin!! Just a moment...I need to calculate a few values.");


            if (timeOutinMS < sysTimeouts.BATTERYIDLETIMEOUT)
                timeOutinMS = sysTimeouts.BATTERYIDLETIMEOUT;
            if (timeOutinMS < sysTimeouts.EXTERNALIDLETIMEOUT)
                timeOutinMS = sysTimeouts.EXTERNALIDLETIMEOUT;
            if (timeOutinMS < sysTimeouts.WAKEUPIDLETIMEOUT)
                timeOutinMS = sysTimeouts.WAKEUPIDLETIMEOUT;

            if (timeOutinMS == 0)
                timeOutinMS = 30;

            Console.WriteLine("OK. I have calculated your computers timeout periods and set the   ");
            Console.WriteLine("necessary hooks. Your computer will not shut off the monitor, will");
            Console.WriteLine("show active in any chat programs,the screensaver is disabled and ");
            Console.WriteLine("the computer will not lock! Anyone looking at you eaither locally ");
            Console.WriteLine("or remotely will think you are hard at work.");
            Console.WriteLine("Now go do something fun...I got your back ;)");
            Console.WriteLine("Oh yeah....if you close this window OR press `q' in this ");
            Console.WriteLine("window you are going to have to actually work.");
            Console.WriteLine("This text will disappear in a 30 seconds. Just in case someone comes ");
            Console.WriteLine("by and reads your screen!");
            Console.WriteLine("Need custom coding? Kenneth.gore@gmail.com");
            while (Console.KeyAvailable == false)
                ConsoleKeyInfo cki = Console.ReadKey(true);

                if (cki.KeyChar == 'q')


        public static void DisableDeviceSleep()
           preventSleepTimer = new System.Threading.Timer(new TimerCallback(PokeDeviceToKeepAwake), null, 0, timeOutinMS * 1000);

        public static void EnableDeviceSleep()

           preventSleepTimer = null;


        private static void PokeDeviceToKeepAwake(object extra)

                   IntPtr Handle = FindWindow("SysListView32", "FolderView");

                   if (Handle == IntPtr.Zero)

                   if (Counter > 1)


        public static void GetSystemTimeOuts()  
            sysTimeouts.BATTERYIDLETIMEOUT = -2;
            sysTimeouts.EXTERNALIDLETIMEOUT = -2;
            sysTimeouts.WAKEUPIDLETIMEOUT = -2;

            if (SystemParametersInfo(SPI_GETBATTERYIDLETIMEOUT, 0, ref batteryIdleTimer, 0) == 1)
                sysTimeouts.BATTERYIDLETIMEOUT = batteryIdleTimer;
                sysTimeouts.BATTERYIDLETIMEOUT = -1;

            if (SystemParametersInfo(SPI_GETEXTERNALIDLETIMEOUT, 0, ref externalIdleTimer, 0) == 1)
                sysTimeouts.EXTERNALIDLETIMEOUT = externalIdleTimer;
                sysTimeouts.EXTERNALIDLETIMEOUT = -1;

            if (SystemParametersInfo(SPI_GETWAKEUPIDLETIMEOUT, 0, ref wakeupIdleTimer, 0) == 1)
                sysTimeouts.WAKEUPIDLETIMEOUT = wakeupIdleTimer;
                sysTimeouts.WAKEUPIDLETIMEOUT = -1;

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  • Sorry....in the above post everything after the phrase "Looking for." is code and should be compiled. It didn't format correctly. The code demonstrates some pretty cool pInvoke for those interested. Btw....after compiled, I just put it in my path somewhere like c:\windows. This way if I'm at a cmd prompt I can type ImWorkin and I'm good to go :) – user205533 Mar 9 '13 at 3:34
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    You can modify your answer by clicking the edit link below it. – Dennis Mar 9 '13 at 3:59
  • please edit your first answer and then delete this one. – teylyn Mar 9 '13 at 4:00
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    WTF is up with the "Just a moment, I'm calculating a few values!" dummy loop? – KalEl Oct 24 '13 at 13:30
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    In response to the c# code posted its usually customary to give credit to the author. That happens to be me. I posted this almost two yeas ago on stack Overflow I believe. – user407607 Jan 11 '15 at 16:59

A lot of these answers are old, and only keep alive through inputs/mouse movement. Compile this in C or C++, this will keep the session alive by setting thread execution state (Windows Only ofcourse)

#include <windows.h>


#define ES_CONTINUOUS       0x80000000
#define ES_DISPLAY_REQUIRED 0x00000002
#define ES_SYSTEM_REQUIRED  0x00000001

int main()
    int result = 0;
        result = SetThreadExecutionState(ES_SYSTEM_REQUIRED | ES_DISPLAY_REQUIRED | ES_CONTINUOUS);
        Sleep(30 * 1000);

    return 0;

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  • I don't use Windows anymore these days but this seems useful. – Gabriel R. Mar 9 at 15:45
  • I guess it is int main() – bracco23 Mar 11 at 16:53
  • A PowerShell equivalent implementation is in superuser.com/a/1596783. – Hexagon 2 days ago

Mouse Jiggler might be an option: https://mousejiggler.codeplex.com/

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  • This works just great :) – sunil Sep 7 '17 at 11:46

I like to use easy and integrated options (no additional software), like a powershell script (thanks https://dmitrysotnikov.wordpress.com/2009/06/29/prevent-desktop-lock-or-screensaver-with-powershell/) that uses the "f15" as the key to success (thx to caffeine. It's indeed least interfering)

param($minutes = 180)

write "... screen will be awake for $minutes"

 $myshell = New-Object -com "Wscript.Shell"

 for ($i = 0; $i -lt $minutes; $i++) {
 write "... screen will be awake for" ($minutes-$i)
 Start-Sleep -Seconds 60    

Put this into a myScriptName.ps1 and start it via desktop shortcut or commandline: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -nop "C:\Users\myUser\Desktop\myScriptName.ps1"

UPDATE: Maybe there was some change from the administrator, but this doesn't work for me anymore Now I have to use an autohotkey-script from NBirnel: https://github.com/nbirnel/nosleep - this work perfect, because it moves the mouse (without distracting any work)

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  • I run the code but getting the following error. Please advise c:\Powershell>powershell -nop myScriptName.ps1 myScriptName.ps1 : The term 'myScriptName.ps1' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. At line:1 char:1 + myScriptName.ps1 + ~~~~~~~~~~~~~~~~ + CategoryInfo : ObjectNotFound: (myScriptName.ps1:String) [], CommandNotFoundException + FullyQualifiedErrorId : CommandNotFoundException c:\Powershell> – Sabrina Nov 15 '18 at 13:24
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    @Sabrina maybe you have to define the full path to your script, so not just "myScriptName.ps1" but "c:\path\to\myScriptName.ps1" – eli Nov 19 '18 at 13:37

In my case just this one line did the trick:


Just put it in the Timer_Tick event and set timer interval to e.g. 60000ms.

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    ok, it's quite late to resume this answer but consider sending not one but two CAPSLOCK if you don't want me to staRT YELLING IN THE MIDDLE OF A STACKOVerflow comment without understanding why (it tooks a couple of minutes to write this comment) – Gian Paolo Sep 3 '18 at 8:31
  • @GianPaolo you're right. This is what I did. I thought it's clear but maybe I should modify the answer. – user3540753 Sep 11 '18 at 7:36
  • And 6 years after answering it’s still a single capslock invoke... smh – enorl76 Jun 10 at 17:01

Extending on Cherona's answer, here is an implementation in PowerShell, using SetThreadExecutionState().

As long the script is running, screen saver and screen lock wouldn't start.

Set-StrictMode -version 3.0

# Definition of SetThreadExecutionState from -
#   http://www.pinvoke.net/default.aspx/kernel32/SetThreadExecutionState.html
#   https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-setthreadexecutionstate
# "EXECUTION_STATE" changed to "uint", added "public" modifier.
$Signature = @'
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern uint SetThreadExecutionState(uint esFlags);

$ES_CONTINUOUS        = 0x80000000L
$ES_SYSTEM_REQUIRED   = 0x00000001L

# Details on Add-Type in https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/add-type?view=powershell-7.
$Kernel32 = Add-Type -MemberDefinition $Signature -Name 'Kernel32' -Namespace 'Kernel32' -PassThru

echo "Forcing system to not go to sleep (disable screen saver)."
echo "Close the window to allow sleep again."
$result = $Kernel32::SetThreadExecutionState($ES_CONTINUOUS -bor $ES_DISPLAY_REQUIRED -bor $ES_SYSTEM_REQUIRED)

# Loop until script is forcibly stopped.
While ($true) {
  Start-Sleep (60 * 60 * 24)  # 24 hours.
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  • Have you tested this? I was under the impression that you need to keep calling SetThreadExecutionState every so often, to reset the "system idle timer" described here docs.microsoft.com/en-us/windows/win32/api/winbase/… – Cherona 2 days ago
  • @Cherona Yes, I verified that this works for many hours (with the lock screen timeout being set to 1 minute). The documentation is indeed vague, but ES_CONTINUOUS could be interpreted as taking care of that. – Hexagon 2 days ago

The correct way to handle it is to:

  • go into the registry where the policy is
  • set the value to whatever you want
  • and alter the registry key permissions
  • only Deny write access to anyone except yourself
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  • 1
    When the admins disable the screen lock settings, editing the registry is already disabled. – Gabriel R. Oct 4 '18 at 15:35
  • @GabrielR. As an administrator you can alter the ACL on the registry keys. If i get the patience i'll link the talk from Mark Russinovish where he mentions getting rid of the Microsoft group policy that locked down his own laptop. If you're an administrator you have full control of the machine. It likely has to start with taking ownership of the registry keys, then granting yourself full control, then denying anyone else anything except read access. – Ian Boyd Oct 4 '18 at 16:43

You should disable the "screen lock"/"sleep mode" from control panel > power options > change plan settings. Her in click the drop down for "Put the computer to sleep" and select "never".

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  • 4
    Domain admins can have a policy-enforced screen lock in Windows. – Gabriel R. Nov 18 '13 at 17:51

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