# How can I prevent a policy-enforced screen lock in Windows?

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?)

• Just curious what "ridiculously short" is?
– Carl
Aug 30 '11 at 15:45
• 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. Aug 31 '11 at 10:32
• The grace period doesn't work for me, while the script does. I assume that my corporate policy also disables the grace period. Apr 20 '18 at 8:41
• 15 minutes for screen locking is absolutely across-the-board standard. It's by no means "ridiculously short" other than OP's ancillary experience and opinion. BTW, this is usually mandated by corporate policy, which IT does not make (we just enforce it or suffer the consequences). Oct 28 '19 at 18:26
• My previous company has a 2-minute screen lock policy. That's not ridiculous but disaster and torturous and sometimes depressing. Dec 27 '19 at 8:07

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.

• 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... Jun 24 '15 at 17:37
• 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 Oct 2 '19 at 7:07
• 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. Jul 23 '20 at 9:14
• Please keep in mind that simulating key presses is a quite brutal way to keep your screen from locking. For a better way, please check my answer out. Nov 23 '20 at 19:20
• @Cfomodz, indeed, I see that they have added the -stes option recently (v1.95 - February 2021). I haven't tested it. My previous comment was written before this option was introduced. If the option does what it promises then it is the same as the CoffeeBean program which I recommended in my previous comment. Sep 2 at 7:04

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.

• 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.) Apr 16 '13 at 11:43
• I confirm that this works on Windows XP using an MP3 file instead of a video. Sep 23 '13 at 9:59
• Brilliant hack!
– user42225
Apr 2 '14 at 13:51
• This also works using VLC for those who prefer it over Windows Media Player
– ecoe
May 5 '14 at 15:22
• Works fine in Windows 7. Nice hack! 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)
Loop

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/

https://chocolatey.org/

• @JoshRivers a way to stop this script, without having to restart the computer, would be nice as well. Feb 3 '17 at 17:52
• @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). Feb 4 '17 at 20:28
• 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 Apr 12 '18 at 15:55
• 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. Jun 6 '18 at 8:30
• Works great on a Win10 Surface laptop - that does not even have a physical NumLock key! 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], $pos[1], 0) Sleep(540000) WEnd This script moves mouse cursor by one pixel in the up-left direction and after that returns it back, then sleeps for 9 minutes (540000 milliseconds). When script is running, you can see AutoIt icon in the tray. You can stop it right-clicking this icon and choosing the corresponding option. To make a script, install AutoIt, right-click in any folder and choose New > AutoIt v3 Script, name it, right-click this new script, choose Edit, paste the code provided above and save. You can even compile it to .exe (again, from context menu) to start, for example, from Windows Scheduler. • Thanks, I'll check it out, seems simpler than a mouse wheel cage setup :) Aug 31 '11 at 10:37 • Precompiled version of this AutoIt Script here symantec.com/connect/downloads/… – JJS Nov 29 '16 at 21:10 A lot of these answers are old, and only keep alive through inputs/mouse movement. Compile this in C or C++, this will keep the session alive by setting thread execution state (Windows Only ofcourse) #include <windows.h> //https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-setthreadexecutionstate #define ES_CONTINUOUS 0x80000000 #define ES_DISPLAY_REQUIRED 0x00000002 #define ES_SYSTEM_REQUIRED 0x00000001 int main() { int result = 0; while(1) { result = SetThreadExecutionState(ES_SYSTEM_REQUIRED | ES_DISPLAY_REQUIRED | ES_CONTINUOUS); Sleep(30 * 1000); } //unreachable return 0; } • I don't use Windows anymore these days but this seems useful. Mar 9 '20 at 15:45 • I guess it is int main() Mar 11 '20 at 16:53 • A PowerShell equivalent implementation is in superuser.com/a/1596783. Oct 24 '20 at 4:46 I like to use easy and integrated options (no additional software), like a powershell script (thanks https://dmitrysotnikov.wordpress.com/2009/06/29/prevent-desktop-lock-or-screensaver-with-powershell/) that uses the "f15" as the key to success (thx to caffeine. It's indeed least interfering) param($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
$myshell.sendkeys("{F15}") } Put this into a myScriptName.ps1 and start it via desktop shortcut or commandline: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -nop "C:\Users\myUser\Desktop\myScriptName.ps1" UPDATE: Maybe there was some change from the administrator, but this doesn't work for me anymore Now I have to use an autohotkey-script from NBirnel: https://github.com/nbirnel/nosleep - this work perfect, because it moves the mouse (without distracting any work) • I run the code but getting the following error. Please advise c:\Powershell>powershell -nop myScriptName.ps1 myScriptName.ps1 : The term 'myScriptName.ps1' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. At line:1 char:1 + myScriptName.ps1 + ~~~~~~~~~~~~~~~~ + CategoryInfo : ObjectNotFound: (myScriptName.ps1:String) [], CommandNotFoundException + FullyQualifiedErrorId : CommandNotFoundException c:\Powershell> Nov 15 '18 at 13:24 • @Sabrina maybe you have to define the full path to your script, so not just "myScriptName.ps1" but "c:\path\to\myScriptName.ps1" – eli Nov 19 '18 at 13:37 • Can be done as an one-liner shortcut: powershell.exe -Command$s = New-Object -com \"Wscript.Shell\"; while(1){write \".\"; $s.sendkeys(\"{F15}\"); Start-Sleep -Seconds 60;} This helps against the policy forbidding PowerShell to execute files. Can be started "minimised" at once. Sep 20 at 11:50 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 • question is asking about Windows.. Jun 24 at 1:39 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 { [FlagsAttribute] 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); [DllImport("USER32.DLL")] 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 + "."; } Thread.Sleep(100); Console.Clear(); Console.WriteLine("You are about to be workin!! Just a moment...I need to calculate a few values."); Console.WriteLine(dots); } GetSystemTimeOuts(); 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; DisableDeviceSleep(); Console.WriteLine(""); Console.WriteLine(""); 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(""); 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(""); Console.WriteLine(""); Console.WriteLine("This text will disappear in a 30 seconds. Just in case someone comes "); Console.WriteLine("by and reads your screen!"); Console.WriteLine(""); Console.WriteLine(""); Console.WriteLine("Need custom coding? Kenneth.gore@gmail.com"); while (Console.KeyAvailable == false) { Thread.Sleep(250); ConsoleKeyInfo cki = Console.ReadKey(true); if (cki.KeyChar == 'q') break; } } public static void DisableDeviceSleep() { SetThreadExecutionState(EXECUTION_STATE.ES_SYSTEM_REQUIRED | EXECUTION_STATE.ES_DISPLAY_REQUIRED | EXECUTION_STATE.ES_CONTINUOUS); preventSleepTimer = new System.Threading.Timer(new TimerCallback(PokeDeviceToKeepAwake), null, 0, timeOutinMS * 1000); } public static void EnableDeviceSleep() { preventSleepTimer.Dispose(); preventSleepTimer = null; } private static void PokeDeviceToKeepAwake(object extra) { Counter++; try { SetThreadExecutionState(EXECUTION_STATE.ES_SYSTEM_REQUIRED | EXECUTION_STATE.ES_DISPLAY_REQUIRED | EXECUTION_STATE.ES_CONTINUOUS); IntPtr Handle = FindWindow("SysListView32", "FolderView"); if (Handle == IntPtr.Zero) { SetForegroundWindow(Handle); SendKeys.SendWait("%1"); } if (Counter > 1) Console.Clear(); } catch { } } 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; else sysTimeouts.BATTERYIDLETIMEOUT = -1; if (SystemParametersInfo(SPI_GETEXTERNALIDLETIMEOUT, 0, ref externalIdleTimer, 0) == 1) sysTimeouts.EXTERNALIDLETIMEOUT = externalIdleTimer; else sysTimeouts.EXTERNALIDLETIMEOUT = -1; if (SystemParametersInfo(SPI_GETWAKEUPIDLETIMEOUT, 0, ref wakeupIdleTimer, 0) == 1) sysTimeouts.WAKEUPIDLETIMEOUT = wakeupIdleTimer; else sysTimeouts.WAKEUPIDLETIMEOUT = -1; } } } • 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 :) Mar 9 '13 at 3:34 • You can modify your answer by clicking the edit link below it. Mar 9 '13 at 3:59 • please edit your first answer and then delete this one. Mar 9 '13 at 4:00 • WTF is up with the "Just a moment, I'm calculating a few values!" dummy loop? Oct 24 '13 at 13:30 • 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 Mouse Jiggler might be an option: https://mousejiggler.codeplex.com/ • This works just great :) Sep 7 '17 at 11:46 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);
'@

$ES_AWAYMODE_REQUIRED = 0x00000040L$ES_CONTINUOUS        = 0x80000000L
$ES_DISPLAY_REQUIRED = 0x00000002L$ES_SYSTEM_REQUIRED   = 0x00000001L

$Kernel32 = Add-Type -MemberDefinition$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.
}
• 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/… Oct 24 '20 at 8:10
• @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. Oct 24 '20 at 9:37

I have created a tiny tray icon application CoffeeBean which uses a much better and reliable way to simulate user's activity by using SetThreadExecutionState WinApi function which is designed almost exactly for this type of use case (for instance, it is the function which is used by video players to keep your screen on while you are watching a film). If you are familiar with Autohotkey, as an alternative, you can use this Autohotkey script.

• The key thing here is SetThreadExecutionState - thank you! It's then a moments work to create an app/script/whatever and use Task Scheduler to run it every 10 minutes. May 28 at 18:25
• @RhysJones, I'm not sure running it once per 10 minutes is going to work well. You don't need to run it periodically. You just need to run it once and keep the process alive. As long as the thread which called SetThreadExecutionState function is alive, OS is not going to lock the screen. That is the idea behind my tray icon application and the Autohotkey script. Jun 1 at 6:50
• You are right - as Hexagon has also noted, the docs are not very precise. Jun 2 at 5:56

I've been using Mouse Move this for ages now. Advantage over Caffeine, options are customisable via GUI.

The Windows 10 version seems new, needs to be installed from Windows Store. Recommend the older one since is portable.

This is a solution which works for Win10 and with MS Office (that is, PowerPoint) installed:

MS PowerPoint (if MS Office is installed). Hit F5 to start "presentation mode". Now move to a different "desktop" (so that the "presentation" doesn't interfere with your actual work) by pressing Windows-logo + Tab, and you're good to go :)

PS: it might also work for Win7 without multiple "desktops", e.g. with Alt + Tab.

In my case just this one line did the trick:

SendKeys.Send("{CAPSLOCK}{CAPSLOCK}");

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

• 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) 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. Sep 11 '18 at 7:36
• And 6 years after answering it’s still a single capslock invoke... smh Jun 10 '20 at 17:01
• Great if this answer could be put into context... e.g. save it as a script, execute in cmd, ... ? - on second thought, other answers provide the context, e.g. superuser.com/a/836346/183485 Jan 4 at 11:14

I love @JoshRivers 's solution of VB script. And I updated a little bit to stop it with duration time.

Dim objResult
Dim intervalSec
Dim durationSec
Dim cnt

intervalSec = 60
durationSec = 3600

cnt = 0

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

Do While True
objResult = objShell.sendkeys("{NUMLOCK}{NUMLOCK}")
Wscript.Sleep (intervalSec*1000)
cnt = cnt + 1
If durationSec <= (intervalSec * cnt) Then
Exit Do
End If
Loop

Everyone else are writing scripts to fake being at the keyboard.

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