In other words, I’m fairly confident I’ve narrowed down when the blanking started—to the February 28, 2025 release (10.2.1712.0). I had originally thought the issue began sometime in late April or early May, but as I mentioned in one of my earlier posts, I didn’t note the exact date. It probably only started to dawn on me gradually after applying that update—which I likely didn’t install immediately when it became available.
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The issue of the monitor going to sleep when closing eM Client seems to have stopped: the last time was a week ago.
This may be related, but it looks like eM Client has updated to version 10.3.2619. I have no specific memory of this update happening—been extremely busy lately—but it’s possible that I let the program update and forgot about it. I’m not aware that eM Client will update without the user’s permission, I only ever remember it telling me than an update was available and did I want to install it.
Anyway, if the update is the reason that the problem was solved, I’m happy with the outcome. 
Well, I spoke too soon. 
It happened again tonight.
There’s no discernible pattern to the monitor blanking when eM Client is closed after being open for more than a certain amount of time. It didn’t happen last night, but it happened two nights and three nights ago, and then not for more than a week before that.
There does seem to be one consistent improvement, though: Now when the monitor goes dark, it’s only for a second or two and then whatever else had been up on the screen comes back.
I can’t believe that I managed to miss @Michael_Premo’s excellent report on this issue! Wouldn’t you know it, I too use NirCmd (version 2.8.6.231).
There are three computers connected to my monitor (HDMI/DVI/VGA); I began using that little program a couple of years ago when the button on the monitor to change the video input stopped working, no doubt from excessive use.
So Michael and I have NirCmd in common. I have no doubt but that our combination of eM Client and NirCmd is at the root of our issue. Michael, if you have found or devised a different way to make the monitor go to sleep, and if that has solved the problem at your end, I’d be curious to try it. Since my last report, after going several more days without the screen blanking issue occurring at all, now the monitor has gone to sleep again the last two nights when closing eM Client.
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Well, I think this pretty much unequivocally points to nircmd—even though I’m still convinced the February 28, 2025 release (10.2.1712.0) actually triggered the issue. Either way, glad I could help!
As an alternative method for blanking my monitors, I wrote an AutoHotkey script that simulates the “Turn off the display” action from Windows Power Options. Since it sounds like you might be using nircmd a bit differently, though, I’m not sure my solution would apply.
Still, if I’ve misunderstood, I’d be happy to share the script—or even just provide the basic command to trigger the monitor power-save “blank” state.
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I’m using a desktop shortcut to NirCmd to turn the monitor off. Here’s the shortcut:
C:\Users\xxxxx\Downloads\nircmd-x64\nircmd.XXX cmdwait 1000 monitor off
Check how this compares to what you’re using and let me know, thanks!
Absolutely - I’m using AutoHotkey v2, and here’s a simple way to blank the screen (i.e., turn off the monitor):
AppsKey:: {
Sleep(1000)
SendMessage(0x112, 0xF170, 2,, "Program Manager")
}
If you’re new to AHK:
AppsKeyis the key that triggers this particular script but you can replace it with any other key. For example, to trigger with the F12 key, useF12::
If you’d prefer to run this as a desktop shortcut instead of using a hotkey:
- Remove the hotkey line (
AppsKey:: {) and the closing brace (}), so the script looks like this:
Sleep(1000)
SendMessage(0x112, 0xF170, 2,, "Program Manager")
- Save it as a
.ahkextension - Place the file on your Desktop (or elsewhere and “Create shortcut” on your Desktop)
- Simply double-click it whenever you want to blank the screen
As far as I know, this is probably the simplest way to do it (other than nircmd
). AHK is a powerful tool, the documentation is solid and the community is very helpful, but there is a learning curve. If someone has a better way, I’d love to hear it!
Also, I’ve worked out a version that shows a countdown popup before blanking the screen with a cancel button if you’re interested…
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In Windows I created a batch script that uses the “powercfg.exe” and “scrnsave.scr” executables included in System32 to sleep my 3 monitors. I then assign that batch script to run with a specific mouse button click. Doing this has caused no issues with my eM Client install.
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For Reference Only - The blanking “problem” returns using the following method:
So, @lancealot inspired me to find another way that doesn’t rely on external programs. (I originally went with AHK since I was already using it for other tasks, so it was just easier to plug in additional parameters to blank my monitors).
I tested out a way using PowerShell—all you need to do is write a .ps1 script, save it somewhere, and have a .bat file on your Desktop call it when double-clicked.
monitorOff.ps1 file:
Add-Type @"
using System;
using System.Runtime.InteropServices;
public class MonitorControl {
[DllImport("user32.dll")]
public static extern int SendMessage(int hWnd, int hMsg, int wParam, int lParam);
}
"@
Start-Sleep -Seconds 1
[MonitorControl]::SendMessage(0xffff, 0x0112, 0xF170, 2)
.bat file:
@echo off
powershell -ExecutionPolicy Bypass -WindowStyle Hidden -File "C:\Path\To\monitorOff.ps1"
exit
I still prefer my original suggestion using AHK as it lets me combine everything I use AHK for into a single script. @lancealot’s approach seems good too, but in my opinion this PowerShell method more closely mirrors what you were already doing.
Note: I only briefly tested this PowerShell method—hopefully it works OK if you decide to use it.
Again, the blanking “problem” happens when closing emClient using this PowerShell method… At least it’s documented here now so no-one wastes time trying it… I guess I’m back to recommending my original AHK suggestion
.
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Thanks for this script. 
I’d heard of AutoHotkey, but the name is all I knew about it. I’ll try it out as soon as I get the chance. (Hectic last few days.)
The AppsKey, is that the same as the Menu key that sits to the right of the space bar, next to the right-hand Control key?
BTW the screen blanking issue hasn’t recurred since the last time I reported it. Can’t find a pattern to its happening vs. not happening other than the length of time eM Client was open, but even that doesn’t seem to hold every time.
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No problem.
The AppsKey is in a different location on every keyboard—some don’t even have one. If you want to identify whether you have one you’ll need a Key Identifier. In fact, AHK can help to identify key scan codes directly.
That said, as I mentioned in my example, you can easily modify the script to trigger with any key you prefer. Or just mimic what you have already been doing and create a shortcut on your Desktop.
Regarding the screen blanking issue: I’ve confirmed that timing is not a factor. The blanking only occurs after using nircmd to turn off the monitors while emClient is running.
If you can confirm this on your end, I think I can safely mark the thread as “Solved.” I just want to make sure it’s resolved for you as well.
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I just copy-and-pasted your shortened script and created a desktop shortcut, then clicked on it and… the monitor went to sleep! Then I wiggled the mouse and the monitor woke back up. Very nice, thank you.
Based on your experience, I don’t expect eM Client to put the monitor to sleep when I close the program tonight. If it does, I’ll be sure to report it. I can also try the alternatives including the one that @lancealot uses. But for now at least, it looks like we can close out this topic.
Thanks again!
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Excellent! I’m glad it worked. Here’s to the problem staying gone 
.
Just one important note: If nircmd has been used at any point since your last reboot, the unwanted blanking will still occur—so don’t be surprised if it happens once more..
As for marking the thread “Solved,” I think I’ll put together a quick synopsis post for anyone else who might run into this—since the details are scattered across the thread.
Definitely keep me posted, especially if the issue reappears. I’m curious to see if it stays resolved long-term. Either way, I’m glad we got this squared away!
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Solved – Final Summary:
For anyone looking at this in the future, it’s now confirmed that for both users affected by this issue, nircmd acts as the trigger. I initially thought the duration eM Client had been open was a factor, but that turned out not to be the case—what matters is whether nircmd has been run since the last reboot. If it has, then closing eM Client will immediately trigger the unwanted blanking (see post #16).
I later found that blanking the monitors via PowerShell also triggers the same behavior, so it’s not limited to nircmd alone (see post #29).
I’d like to emphasize that this issue began with eM Client version 10.2.1712.0 (Feb 28, 2025). Prior to that, nircmd worked without causing any problems (see post #17–#21).
To resolve it, I wrote an AHK script that avoids the issue entirely (see post #27). All the details, testing, and context are documented throughout the thread.
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