Created by Salil Maniktahla on 09/29/2004. Modified: 09/29/2004 08:30


An error was encountered while opening a window


When I exit notes and then run notes again, I get the following message:
"An error was encountered while opening a window"

and then Notes crashes. A reboot generally fixes the problem, but it seems as though a process isn't terminating properly and there's state information being kept in a file somewhere.


I solved the problem by removing all *.nsf files and dsk;ndk files. Didn't have the time to check which one of them causing the problem.

David Engqvist on 10/05/2004 07:39

At command prompt run "nsd -kill" from within the notes directory.

Tommy Sellers on 10/13/2004 09:47

If notes crashes, goto taskmanager and end notes application, and then goto processes and end tskldr.exe and restart notes.

Ed Delaney on 10/22/2004 22:23

If notes crashes, goto task manager and end the Lotus Notes application and then goto processes tab and highlite ntaskldr.exe and end the process and then reopen Lotus Notes.

Ed Delaney on 10/22/2004 22:31

I had Notes Minder running when Notes caused this error. I terminated Minder, ntaskldr.exe, and was able to restart Notes.

Bill on 01/18/2005 09:27

All good suggestions. We've also built our own "Notes Restart", since even NTaskldr, which is supposed to track Notes client crashes, sometimes fails. We just make a list of all EXEs in the Notes folder & try to kill them, then restart Notes.

However, I came into this thread looking for something slightly different (same error though). We had the same error in our environment but only when some users started Notes. Ended up being user error. We had put an icon in the Quick Launch bar. Since those are single-click icons, users get confused & double click. If you time it slow enough, the second click really counts & tries to start a second Notes instance, which we all know won't happen. Same might happen if there's desktop icon that's set to react on single click.

Volker on 02/02/2005 13:13


Volker - wrong. Period.

sd - typical windows/intel BOFH response.

Ed Delaney - what planet is he from ?

Tommy Sellers - absolutely correct.

Engqvist - you gotta be kidding me. If he's not kidding, his advice isn't wrong, it's dangerous.

Umm no on 02/02/2005 21:31

I deleted 2 process through task manager. NTASKLDR and NSL.

stanh on 02/04/2005 07:23

Hi everyone!

I am running a program called ClientSync in an effort to get Notes (6.0.3) to run on Citrix (Metaframe XP Pres Server 1.0, on Win2003). ClientSync calls Notes, which sometimes hangs.

Error message: "An error was encountered while opening a window."

The process that hangs is "nfilertn.exe". Once nfilertn.exe becomes resident, the Notes client will not successfully start until I use Task Manager to terminate the process.

If the client starts successfully, "nfilertn.exe" will not be resident when Notes presents its workspace.

I have not been able to find a way to force a failure. I estimate that the process hangs about 20% of the time (Often, the process will work for 20 times in a row.).


Roger Reynard on 02/17/2005 13:20

I received a fatal exception when I tried the "nsd -kill" command. Killing the NTASKLDR task works quite well though. I'd say Ed was right.

Martin Lylyk on 05/11/2005 10:19

just end the process ntaskldr ,you will definately free from this problem

Hitesh on 05/13/2005 04:38

I have downloaded ZAPNOTES utility and now it works great

MLD on 06/23/2005 03:25

Reboot Reboot Reboot...quickest, easiest for non-proficient users.

CMoore on 06/23/2005 08:05

Volker is exactly correct. Period. This is caused by double-clicking the quick-launch icon. The first instance of Notes builds correctly. An additional instance attempts to build and appears behind the good one with the stated error displayed. When the user shuts down Notes, it does so correctly, then displays the error message created from their original double click that's been hiding this whole time.

Tommy Sellers: is correct, but it only fixes the problem. It doesn't address the cause. Volker does.

Brooklynegg on 07/05/2005 16:41

Thanks all, killing ntaskldr works like a charm on XP/Notes 6.5.1.

The only thing our wonderful 'Support Center' could offer is the same lame advice they give everyone; reboot!

If they would have spent 5 min looking for a real solution and communicated it to the 13k+ EEs here and the other tech support people I would guess it would save hunderds of hours of time a year.

Anyway, Thanks.


DeP on 07/12/2005 08:26

We get the problem following a "delayed write error (OK I know we shouldn't have notes file son a network drive, but...). We have an automated launch profgram that checks for residual tasks and then launches NSD.exe -Kill. For some reason it is not killing the ntaskldr.exe. Any ideas why?

Killing Ntaskldr.exe from Task manager works as does rebooting, but would prefer the "supported" solution using NSD.

Alan C

Alan Cuthbertson on 09/13/2005 06:12 PM

Just a note to add:

When you have the same problem for Domino Admin. i.e you cannot open it and you get the "An error was encountered while opening a window" you have to stop two processes. The ntaskldr.exe as all have been saying, and the nevents.exe process as well.

Just stopping the ntaskldr.exe for Domino Admin does not work alone.

Tammy Bands on 11/23/2005 06:42 PM

Download zapnotes from here:


Jukka P on 02/07/2006 06:46 AM

Its not just caused by double clicking. We have Notes shortcut in startup for All Users, but if anyone adds it to the start up in their own profile as well the same error occurs as its trying to load the program twice, so may be worth checking for that.

Slingo on 03/23/2006 01:55 AM

This situation seem to be caused by abrubt termination of notes. Reboot is the best solution if your users are not techie enough. The killing of processes is a bit dangerous if your talking to a user on the phone, but I found it usefull on my own workstation when I have more than enough running processes.

Ezza on 06/07/2006 01:22 AM

Killnotes works just fine for fixing this problem as well. Download from here: {Link}

Lars Carlsson on 07/05/2006 12:03 AM

I tried both "nsd -kill" and tried to delete nlnotes.exe and ntaskldr.exe from the Task Manager , and it WORKED !!!! a big THANK YOU

Tanuj Anand on 01/29/2007 05:46 AM

Best way to fix this is to use the uninstall feature of the OS to get rid of notes all together. It has to be the worst application that I've ever had to use. Crashes all the time. Its slow when it does run. Has the UI of applications of 10 or more years ago. And it sucks at its most common purpose: Email.

How many other application do you have to go through the BS above to just to restart the app. Having the users use the command prompt to run the 'nsf -kill' command? Must users will simply have to reboot. I cringe everytime I start notes.

K on 02/07/2007 08:13 AM

Thanks for the suggestions. Everytime my notes used to crash, which did today again, I used to reboot!

Today I was looking for a solution, and I didn't wanted to reboot again and I got the answer!

"nsd -kill" worked like a charm.

Now I know the solution and will save lots of time.

Arindam Basu on 02/14/2007 12:31 AM

Thanks t u all who helped me to the problem resolved

Ritchie on 06/01/2007 02:03 AM

i have this prob all the time.

download kill domino


jazz on 10/10/2007 01:04 AM

Actually this error caused due to unexpectedly closing the applications running on the Domino.Due to various processes are running and stopping them forcefully (instances) causes such errors.

The solution is 1.Restart the Lotus Notes Server

or.2. run "nsd-kill" or

3.End "ntaskldr.exe" and restart Notes

Rawhim Naik on 11/05/2007 12:48 AM


Many good suggestions!

Now what if the hanging client is ON the server (launch using C:\Lotus\Domino\nlnotes.exe) ?

1-Running killNotes (or other Notes Medics) would be a VERY BAD idea. Because it would kill the server too!

2-No task ntaskldr is running.

3-nlnotes had been killed but still no help…

4- Deleting file pid.nbf (in notes/Data) neither help

5 – unable to delete the ~notes.lck file because it’s used by the nserver.

Well boot of course will help, but …. It’s a server :-(

Emmanuel GLEIZER on 11/11/2007 07:11 AM

I encountered it while trying to open a .nsf file from the OS level viz. trying to launch the database (by double-clicking on it in Windows Explorer) while Lotus Notes is running. The databases otherwise open normal when opened from within Lotus Notes (i.e. File->Database->Open). Any inputs why this is happening?

On the surface it behaves like a file-association issue (though doesn't seem to be).

RV on 12/13/2007 12:37 AM

Just go to 'Task manager'

Click on 'Processes' Tab > kill ntaskldr.exe.

Keerthan on 12/29/2007 01:51 AM

CMoore Are you crazy ???

tamamo on 01/25/2008 03:51 AM

> Just go to 'Task manager'


>Click on 'Processes' Tab > kill ntaskldr.exe.

> Keerthan on 12/29/2007 01:51 AM

This worked for me (tried it on more than one occasion.

Mark on 02/21/2008 10:28 AM

I couldn't find ntaskldr in my task manager when I experienced this issue. I tried the prompt but I think my admin disabled the CD command because it wouldn't go to the C drive. I did download the Zapnotes application and it worked! I do agree with K in saying to uninstall Notes, I don't really care for the application myself but when the company you work for has it as their e-mail client, you really don't have a choice...

rachelm920 on 03/31/2008 09:21 AM

End all process by doing a cold boot!

Remedy on 05/20/2008 11:26 AM

This error occurs only if you do not close the notes properly the best solution offered is restart the pc or run zapnotes 3

or go to taskmanager and end the process notesrunner.exe or you can also go to notes folder and delete cache.ndk and `notes.lck

this should solve the problem

ranganath on 08/23/2008 11:01 PM

"nsd -kill" worked for me, i ran it from c:\program files\notes\ directory

Amar Nath on 11/11/2008 08:55 AM

"nsd -kill" worked like a treat! thank you!

Dexter on 12/01/2008 01:38 PM

Because of the way we are setup I had to move nsd.exe to the directory where our notes.ini file is located. Then I made a batch file that runs nsd -kill works great. Thank you for your help Tom.

@Echo Off

Echo This will stop any notes processes so you can start Notes.



cd "D:\userdata\John_Notes\Data"

nsd -kill

Echo Done


Xerolooper on 01/05/2009 01:04 PM

nsd -kill from Lotus notes directory worked for me.

AR on 03/16/2009 05:12 AM


Anonymous on 03/16/2009 09:25 AM

I work via a Citrix remote desktop and therefore have no privs to run/delete anything. I have had this Notes issue occur repeatedly and have gone days before I am able to log in (only after either the mail server is rebooted or the remote server that I connect to is rebooted). I can't delete the ~notes.lck file so just wondered if there is a specific order of files I can try to delete in the notedata directory that will eventually free things up.

kris on 03/25/2009 08:06 PM

I restarted Notes after terminating ntaskldr.exe process

Raj on 04/03/2009 09:13 AM

Go To the Task manager and kill the process nkldr.exe

and start ur lotus notes it will get started

Mayank on 04/24/2009 05:30 AM

"nsd -kill" worked for me. Of course the reason i got into this mess is that notes was hanging bad while starting up and replicating the address book, so I killed notes via task manager, then couldn't launch it again.

a on 11/02/2009 09:14 AM


IF u get the error message " An error was encountered while opening a window " while running notes ..

Run the command :

c:\notes\nsd.exe -kill

jatinchakravarty on 12/11/2009 01:55 PM

If notes crashes, goto taskmanager and end notes application, and then goto processes and end ntaskldr.exe and restart notes.

Sudhanshu Pandey on 02/22/2010 11:41 PM

Hi guys,

Killing ntaskldr service is works with Lotus Notes, But which service should be killed when Domino Admin client get crashed??

Please help.

Lalantha on 04/25/2010 11:57 PM

All previous suggestions failed, I had to kill (also) nfilret.exe .

Jfs on 06/10/2010 03:12 AM

Thanks Ed Delaney. Killing the ntaskldr worked.

JD on 07/14/2010 07:18 AM

Killing "ntaskldr.exe" process worked for me.


Vimal on 09/06/2010 06:57 AM

Terminated the process ntaskldr.exe in the Task Manager and then able to Open Notes.

Suresh on 09/29/2010 10:53 PM


if notes crashes, goto task manager and end the Lotus Notes application and then goto processes tab and highlite ntaskldr.exe and end the process and then reopen Lotus Notes.Ed Delaney on 10/22/2004 22:31


Works for me......Thanks...

Jelden on 01/26/2011 09:57 PM

End the ntaskldr.exe in processes tab of taskmanager.It worked....

Geetha on 06/03/2011 01:32 AM

I had a user with this problem and the lock files was still there so i deleted and it work again

drakir on 08/26/2011 09:29 AM


HAO on 08/27/2011 10:05 AM

When you get this error message go to your task manager and goto process tab and delet all the files which strts with "n" except your notepad if its open, than restart notes it will definately work.

Subhadeep Das on 04/20/2012 07:12 PM

Ending "ntaskldr.exe" process worked.

But I have to do this every time when I close Notes...

DK on 07/25/2013 07:49 AM

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