Notepad++ v8.7.1 (32-bit) NppShell.dll is intermittently crashing Windows Explorer.

xomx

It is a buffer overflow caused somehow by the NppShell.dll in the Windows Explorer process. As a temporary workaround, you can disable this shell extension by going to your C:\Program Files (x86)\Notepad++\contextMenu\ folder and run there this command in cmd (with admin rights): regsvr32 /u NppShell.dll

This is a known problem for some users (they reported it for x64 too) but unfortunately I was not able to reproduce it, so I cannot say if it is a problem of NppShell shell extension, Notepad++ app or some other SW. It can also be a conflict with some other shell extension installed in your system (otherwise I cannot explain why most Notepad++ users do not have this problem).

If you switch to x64 Notepad++ with its x64 NppShell and you still get these Explorer crashes, you can try to follow these instructions to help me with debugging of the issue:
https://github.com/notepad-plus-plus/notepad-plus-plus/issues/15683#issuecomment-2492113826

@Mark-Colvin said in Notepad++ v8.7.1 (32-bit) NppShell.dll is intermittently crashing Windows Explorer.:

OS Name : Windows 8 Pro (64-bit)

I am also surprised to see this info when according to your post it should be reported as Win10 or Win11.

xomx

@Mark-Colvin

Could you please report your Windows Registry relevant info:

Save the following to a file (named e.g. WinVerRegKeys-export.cmd) somewhere writable on your disk:

PowerShell "$Key='HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion'; Get-ItemProperty -Path $Key -Name *" > WinVerRegKeys64.txt
PowerShell "$Key='HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows NT\CurrentVersion'; Get-ItemProperty -Path $Key -Name *" > WinVerRegKeys32.txt

Run the WinVerRegKeys-export.cmd batch file by e.g. doubleclicking on it in Explorer.
Take the contents of the created WinVerRegKeys32.txt and WinVerRegKeys64.txt files and post them please here.

Mark Colvin

@xomx ,
posted here are the files you requested.

Also, I uninstalled NPP x32 and not seen any Windows Explorer errors nor crashes for over 48 hours. (normal laptop usage, about 6 to 10 hours per day)

WinVerRegKeys32.txt


BaseBuildRevisionNumber   : 1
BuildBranch               : ge_release
BuildGUID                 : ffffffff-ffff-ffff-ffff-ffffffffffff
BuildLab                  : 26100.ge_release.240331-1435
BuildLabEx                : 26100.1.amd64fre.ge_release.240331-1435
CompositionEditionID      : Enterprise
CurrentBuild              : 26100
CurrentBuildNumber        : 26100
CurrentMajorVersionNumber : 10
CurrentMinorVersionNumber : 0
CurrentType               : Multiprocessor Free
CurrentVersion            : 6.3
DisplayVersion            : 24H2
EditionID                 : Enterprise
EditionSubManufacturer    : 
EditionSubstring          : 
EditionSubVersion         : 
InstallationType          : Client
InstallDate               : 0
ProductName               : Windows 10 Enterprise
ReleaseId                 : 2009
SoftwareType              : System
SystemRoot                : C:\WINDOWS
UBR                       : 2894
RegisteredOwner           : __________@gmail.com
PSPath                    : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windo
                            ws NT\CurrentVersion
PSParentPath              : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windo
                            ws NT
PSChildName               : CurrentVersion
PSDrive                   : HKLM
PSProvider                : Microsoft.PowerShell.Core\Registry

WinVerRegKeys64.txt



SystemRoot                : C:\WINDOWS
BaseBuildRevisionNumber   : 1
BuildBranch               : ge_release
BuildGUID                 : ffffffff-ffff-ffff-ffff-ffffffffffff
BuildLab                  : 26100.ge_release.240331-1435
BuildLabEx                : 26100.1.amd64fre.ge_release.240331-1435
CompositionEditionID      : Enterprise
CurrentBuild              : 26100
CurrentBuildNumber        : 26100
CurrentMajorVersionNumber : 10
CurrentMinorVersionNumber : 0
CurrentType               : Multiprocessor Free
CurrentVersion            : 6.3
DisplayVersion            : 24H2
EditionID                 : Professional
EditionSubManufacturer    : 
EditionSubstring          : 
EditionSubVersion         : 
InstallationType          : Client
InstallDate               : 1732282151
LCUVer                    : 10.0.26100.2894
ProductName               : Windows 10 Pro
ReleaseId                 : 2009
SoftwareType              : System
UBR                       : 2894
PathName                  : C:\Windows
PendingInstall            : 0
ProductId                 : 00330-53097-84373-AAOEM
DigitalProductId          : {164, 0, 0, 0...}
DigitalProductId4         : {248, 4, 0, 0...}
RegisteredOwner           : __________@gmail.com
InstallTime               : 133767557516344286
PSPath                    : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows 
                            NT\CurrentVersion
PSParentPath              : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT
PSChildName               : CurrentVersion
PSDrive                   : HKLM
PSProvider                : Microsoft.PowerShell.Core\Registry

Sorry, not enough karma to attach files to posts yet. Supplied as code.

Mark
—
moderator edited to remove real email address

xomx

@Mark-Colvin

Thanks.
But I didn’t find anything wrong in your data (that could explain your previously reported Win8).

But all this gives me the idea that perhaps the affected users here have something unusual/wrong in their Registry, which in turn causes the N++ shell extension to crash. I have checked the NppShell source code and indeed - some parts of the code are not the best in terms of resilience to unexpected input or some resource or data unavailability. I didn’t manage to crash Explorer exactly the same way as all affected users report, but in principle that could be it (maybe I just didn’t simulate the right bad data in the Registry).

I’ll try to raise some questions in the NppShell project issues.

Mark Colvin

@xomx ,

Update: I installed npp.8.7.5.Installer.x64 five days ago without Context Menu feature and fewer plugins. So far, no Windows Explorer crashes.

I really miss the Context Menu feature, NPP is so easy to open many file types with this quick step for a quick peek.

I will re-configure NPP soon with Context Menu turned on and see if the problem returns. Any advice on data collection for this issue if it re-occurs?

TIA,
Mark

xomx

@Mark-Colvin said in Notepad++ v8.7.1 (32-bit) NppShell.dll is intermittently crashing Windows Explorer.:

Any advice on data collection for this issue if it re-occurs?

As I already said:

@xomx said in Notepad++ v8.7.1 (32-bit) NppShell.dll is intermittently crashing Windows Explorer.:

If you switch to x64 Notepad++ with its x64 NppShell and you still get these Explorer crashes, you can try to follow these instructions to help me with debugging of the issue:
https://github.com/notepad-plus-plus/notepad-plus-plus/issues/15683#issuecomment-2492113826

So if you can, please follow the instructions in that GitHub comment and then somehow forward me the relevant Explorer crash dump file generated along with a possible NppShell.log.

If the GitHub procedure seems too complicated for you - the main thing is to get the crash-dump file while using my special version of the “C:\Program Files\Notepad++\contextMenu\NppShell.dll”, so download it and after the usual reinstall of your Notepad++ with the shell context extension, replace the standard NppShell.dll file there with the file from this archive: https://github.com/user-attachments/files/17850910/NppShell_v1500_x64_Debug.zip

If you have any questions about the GitHub instructions, do not hesitate to ask me.

Mark Colvin

@xomx ,
Thank you for the alternatives on this investigation. I will update as I get more information.

Thanks again,
Mark

Mark Colvin

@xomx,
Posted dump file and error dialog at:
https://github.com/notepad-plus-plus/notepad-plus-plus/issues/15683#issuecomment-2492113826

Saw when open .ZIP file… got the error dialog, clicked retry, and all explorer windows vanished.
Hope it helps…

Mark Colvin

@xomx,
5 hours later, another error with NppShell.DLL, but no new dump file created.
This occurred during a copy/paste operation from one Window to another.

xomx

@Mark-Colvin

Could you please check if you are not running N++ in Windows8 compatibility mode? More about it here.

Mark Colvin

@xomx
How does this compatibility mode affect the Explorer context menu invocations?
The one Shortcut I have is NOW set to Compatibility mode with Windows 8. But rarely use it directly…

What about the errors with NppShell.DLL which occur without NP++ even turned on?
(I am missing something on how this NppShell.DLL works outside of NP++)
See NppShell.log files posted in github thread…

Thanks,
Mark

xomx

@Mark-Colvin said in Notepad++ v8.7.1 (32-bit) NppShell.dll is intermittently crashing Windows Explorer.:

How does this compatibility mode affect the Explorer context menu invocations?

Good point, this probably influences the N++ app only and not the NppShell extension DLL invoked by the shell Explorer.

David MS

Hello,

I have also constantly the problem that NppShell.dll crashes the Windows 11 Explorer.
After uninstalling Notepad++ the explorer runs without crahes.

I use the latest version of Notepad++ (8.7.9).

Does exists a workaround or a fix?

Thank you very much.

Best regards,

David

xomx

@David-MS said in Notepad++ v8.7.1 (32-bit) NppShell.dll is intermittently crashing Windows Explorer.:

Does exists a workaround

If you mean by this a workaround to not have to completely uninstall the N++ for preventing the Explorer crashes, then yes - unregistering of the NppShell context-menu handler helps: https://community.notepad-plus-plus.org/post/99261

or a fix?

I could not exactly reproduce the issue myself but found some potential problematic places in the NppShell source code and put a “hardening” of that code to my TODO. Unfortunately not enough free time yet. More info and possible future progress in the GitHub issue.