[Bug]: Explorer.exe crashes, nccontextmenu.dll unloaded

[Tampa]

⚠️ Before submitting, please verify the following: ⚠️

• This is a bug, not a question or a configuration issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server and Desktop Client are up to date. See Server Maintenance and Release Schedule and Desktop Releases for supported versions.
• I agree to follow Nextcloud's Code of Conduct

Bug description

Installed update today after prompted. Looked as normal, no errors during installation.
Right click any file in windows explorer causes explorer.exe to crash. Event viewer shows:

Faulting application name: Explorer.EXE, version: 10.0.19041.4170, time stamp: 0x441d086f
Faulting module name: NCContextMenu.dll_unloaded, version: 3.0.0.47, time stamp: 0x65fae7f1
Exception code: 0xc0000005
Fault offset: 0x0000000000001010
Faulting process id: 0x30b0
Faulting application start time: 0x01da7bfa18bd93da
Faulting application path: C:\Windows\Explorer.EXE
Faulting module path: NCContextMenu.dll
Report Id: edefb2c8-42dd-4e5d-a036-441e94cb4f7b
Faulting package full name:
Faulting package-relative application ID:

Already tried repairing via the .msi and restarted computer twice. Still the same. Will try uninstall next.

Steps to reproduce

1. Right click on any file

Expected behavior

Context menu popping up

Which files are affected by this bug

NCContextMenu.dll

Operating system

Windows

Which version of the operating system you are running.

Windows 10

Package

Appimage

Nextcloud Server version

28.0.3

Nextcloud Desktop Client version

3.12.2

Is this bug present after an update or on a fresh install?

Updated from a minor version (ex. 3.4.2 to 3.4.4)

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

Are you using an external user-backend?

• Default internal user-backend
• LDAP/ Active Directory
• SSO - SAML
• Other

Nextcloud Server logs

Not applicable

Additional info

client_log.zip

[Tampa]

I uninstalled now and restarted Explorer.exe, so far no crashes.

[AlexDe74]

confirm.
Stack trace:

nextcloud stack trace.txt

Disabling of "Nextcloud context menu handler" with ShellExView from NirSoft solves the problem.

[bambistassis]

Hello,

We've encountered the same issue. Are there any alternative solutions available besides disabling Nextcloud? Additionally, is there a planned upgrade for Nextcloud?

[Tampa]

You could go back to the previous release. From the looks of things nothing critical was changed, so probably fine. I suspect this should be easy to fix given a quick glance at the commits there were only maybe a handful of changes to the context menu handler so it should not be hard to find the suspect commit and fix it.

[sysvwfwsw]

Same issue here. I went back to 3.12.0. and all works fine again.

[Lightning2X]

I can verify I have this bug as well.

[vagner-dias]

Same problem here - running NC 3.12.2 on windows 10 (10.0.19044.4170)

[pand-herber]

We are affected as well - explorer.exe crashes on right-click to open context menu on around 50 windows 10 devices with NC client 3.12.2.

Name der fehlerhaften Anwendung: explorer.exe, Version: 10.0.19041.4170, Zeitstempel: 0x441d086f
Name des fehlerhaften Moduls: NCContextMenu.dll_unloaded, Version: 3.0.0.47, Zeitstempel: 0x65fae7f1
Ausnahmecode: 0xc0000005
Fehleroffset: 0x0000000000001010
ID des fehlerhaften Prozesses: 0x2bd4
Startzeit der fehlerhaften Anwendung: 0x01da7c4acbef3507
Pfad der fehlerhaften Anwendung: C:\Windows\explorer.exe
Pfad des fehlerhaften Moduls: NCContextMenu.dll
Berichtskennung: bdb3b162-f4c3-44ba-915c-311e3f94ce4f
Vollständiger Name des fehlerhaften Pakets:
Anwendungs-ID, die relativ zum fehlerhaften Paket ist:

[daukus]

Probably it's the old style right click modified wich doesn't work anymore. Revert to default.
Problem related to w11, however..

[seedplease]

I am also encountering this error. However it is when I launch explorer. It will crash once when a new file browser window is opened, however reattempting to open explorer a second time after it crashes, everything will be functional. After closing all explorer windows, this pattern will repeat. This is inside of a windows 10 virtual machine running on proxmox.

Faulting application name: explorer.exe, version: 10.0.19041.4170, time stamp: 0x441d086f
Faulting module name: NCContextMenu.dll_unloaded, version: 3.0.0.47, time stamp: 0x65fae7f1
Exception code: 0xc0000005
Fault offset: 0x0000000000001010
Faulting process id: 0x1f44
Faulting application start time: 0x01da7c916f3f60eb
Faulting application path: C:\Windows\explorer.exe
Faulting module path: NCContextMenu.dll
Report Id: 3ebe1650-5991-42da-91bb-47cf3afb4bff
Faulting package full name: 
Faulting package-relative application ID: 

[alpha-tango-kilo]

It will crash once when a new file browser window is opened, however reattempting to open explorer a second time after it crashes, everything will be functional. After closing all explorer windows, this pattern will repeat.

Same behaviour here, Windows 10 on bare metal

[munrobasher]

Repeated at client site with all Windows 10 systems. Where can you download old versions from and why is this still awaiting triage? It's a priority #1 fault.

[jan-klima]

Same here - Win 11 10.0.22631

[EVOTk]

Same for me - Win 10 22H2

[jgonyea]

Same here:

• Windows 10, bare metal
• Windows 10, qemu VM

[Tampa]

Repeated at client site with all Windows 10 systems. Where can you download old versions from and why is this still awaiting triage? It's a priority #1 fault.

https://github.com/nextcloud-releases/desktop/releases

[Eisaichen]

Same here, Win11 bare metal

Faulting application name: explorer.exe, version: 10.0.22621.3296, time stamp: 0x48d2cb32
Faulting module name: ntdll.dll, version: 10.0.22621.3235, time stamp: 0xa2c4352c
Exception code: 0xc0000409
Fault offset: 0x00000000000a43b0
Faulting process id: 0x0x4520
Faulting application start time: 0x0x1DA7CC81F7019E3
Faulting application path: C:\WINDOWS\explorer.exe
Faulting module path: C:\WINDOWS\SYSTEM32\ntdll.dll
Report Id: 1d2254ba-7fa5-4b82-a12f-03c917e3868a
Faulting package full name: 
Faulting package-relative application ID: 

In my system logs, it didn't point to NCContextMenu.dll somehow, but the symptoms are the same and also appear after the latest NC update.

[Cl4whammer]

I can confirm this issue. I updated yesterday and now iam having lots of explorer.exe crashes. I was afraid that the ram i bought 3 weeks ago starts to fail. Currently iam doing a full urbackup restore from last week, will update post to 100% confirm its gone after removing this nextcloud version.

EDIT: System restored, old version of nextclould client is installed and no issues. At least now i know my urbackup server works fine :D

[Lordmau5]

Chiming in as well - frequent Explorer crashes on both the PCs I have Nextcloud installed on.

[ludoc]

I can confirm this issue. I updated yesterday and now iam having lots of explorer.exe crashes. I was afraid that the ram i bought 3 weeks ago starts to fail. Currently iam doing a full urbackup restore from last week, will update post to 100% confirm its gone after removing this nextcloud version.

may be too late but just disable Nextcloud Desktop contextual menu solve the issue (workaround).

To do this, you can use ShellExView software from NirSoft as suggested by @AlexDe74

You can also use a reg file :

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Shell Extensions\Blocked]
"{BC6988AB-ACE2-4B81-84DC-DC34F9B24401}"=""

or from cmd.exe as administrator :

REG ADD "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions\Blocked" /v "{BC6988AB-ACE2-4B81-84DC-DC34F9B24401}"

Then, restart explorer.exe

When the problem will be fixed by Nextcloud team, you should remove this registry entry with :

.reg file :

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Shell Extensions\Blocked]
"{BC6988AB-ACE2-4B81-84DC-DC34F9B24401}"=-

or from cmd.exe as administrator :

REG DELETE "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions\Blocked" /v "{BC6988AB-ACE2-4B81-84DC-DC34F9B24401}" /f

Then, restart explorer.exe

[fridok]

Same here on a Windows 10 system. This is really annoying. Nextcloud team should call all hands on deck and provide a fix asap. Strange that no one from the company seems to bother .

[munrobasher]

Same here on a Windows 10 system. This is really annoying. Nextcloud team should call all hands on deck and provide a fix asap. Strange that no one from the company seems to bother .

That is a rather worrying and testing must have been very limited. Is there anyone reading this who hasn't got the problem?

[Hun73rdk]

I have the same problem used countless hours due to the event viewer pointing at something else so started to uninstall programs until i found out it was nextcloud and its NCContextMenu.dll. and i am on win 10

[vagner-dias]

Maybe this PR is related to the issue?

#6573

[pschneider1968]

I am affected by this Windows Explorer crash, too. Windows 10 Pro 22H2, Build 19045.4170, Windows Feature Experience Pack 1000.19054.1000.0, Nextcloud Desktop App 3.12.2.

[Tally]

Affecting me as well on Windows 22631.3296 with Nextcloud 3.12.2 and I was ready to blame Microsoft.

The registry edit listed by @ludoc seems effective so far. Thank you.

[pschneider1968]

I downgraded NC Desktop to 3.12.1 and the crashes are gone. So it seems 3.12.2 introduced this bug.
Waiting for 3.12.3 now, I guess 😉

[Lord-Nightmare]

Very strangely, I have two NC Desktop 3.12.2 installs, both on Win10 Pro 10.0.19045(22H2); one has the crash on right click(downgrading to 3.12.1 fixed it), and the other does not(and is still on 3.12.2). Curious.

EDIT: this might be a hint:
On the computer which crashes with 3.12.2 and works with 3.12.1, I had created a windows "library" folder specifically for nextcloud, but on the computer which does not crash with 3.12.2, I never did so.

[ghost]

everybody affected by the crash can you test https://cloud.nextcloud.com/s/LFsYCAdFqLaYQB3 ?

Thx, this version solves the problem for me

everybody affected by the crash can you test https://cloud.nextcloud.com/s/LFsYCAdFqLaYQB3 ?

The problem is fixed by this version. Thank you!!!

Thanks! Testing.

[vagner-dias]

everybody affected by the crash can you test https://cloud.nextcloud.com/s/LFsYCAdFqLaYQB3 ?

Issue fixed!

One interesting fact: After installing the update and rebooting the computer, no nextcloud context menu was shown and the context menu was taking 2~3 seconds to be shown, so I rebooted the computer again.

After the second reboot everything went back to normal, I mean, NC context menu was shown with no delay and no crashes anymore.

Thanks!

[munrobasher]

Does this mean the website has been updated with the fixed version and I can instruct everyone to upgrade?

[ghost]

No just get the Install fix from the link like everyone else and update your clients once they release a new version the fix will be there also.

[thetruetype]

everybody affected by the crash can you test https://cloud.nextcloud.com/s/LFsYCAdFqLaYQB3 ?

Yes, seems to be working on W11 23H2 as well!

[megmug]

everybody affected by the crash can you test https://cloud.nextcloud.com/s/LFsYCAdFqLaYQB3 ?

This seems to fix the issue on our Win10 machines here, thank you for the hotfix!

[dorianborovina]

everybody affected by the crash can you test https://cloud.nextcloud.com/s/LFsYCAdFqLaYQB3 ?

Thanks! Fixed the issue on my Win10 LTSC N 1809. 👍🏻

[popallo]

Hi all.

Patched version works well under Windows 11 23H2 (22631.3374).

Thx!

[zzzkeil]

everybody affected by the crash can you test https://cloud.nextcloud.com/s/LFsYCAdFqLaYQB3 ?

👍 Windows 11 23H2, over 2 hour without crash now .... 👍

[myCodebox]

Had the same problem (Win11 23H2) - explorer.exe open, close, open and crash
The fix worked for me. (https://cloud.nextcloud.com/s/LFsYCAdFqLaYQB3)

thx

[pcjc2]

Just as an FYI, potentially we see this crash affecting Solidworks (2022), I suspect the dll gets loaded in that case too. Disabled the extension for now, and will see if the issue resolves. If my colleague is brave, we can then try the updated Nextcloud client.

[sveken]

The fix above resolved the crash here too. Nextcloud now keeps prompting for updates but i won't allow it untill its fixed.

[pschneider1968]

Just installed 3.12.3 and the issue is fixed on my PC and laptop with this version! 😀🙏

[Cristy94]

Explorer and WampServer were crashing for me, I updated to 3.12.3, so far no explorer or WAMPP crashes.

[BallonLac]

Just installed 3.12.3 and the issue is fixed on my PC and laptop with this version! 😀🙏

Same here (crash in ntdll.dll with 3.13.0).

[PeterTucker]

everybody affected by the crash can you test https://cloud.nextcloud.com/s/LFsYCAdFqLaYQB3 ?

Link is dead. Can I get the fix?

Using Windows 10

[PhilippSchlesinger]

everybody affected by the crash can you test https://cloud.nextcloud.com/s/LFsYCAdFqLaYQB3 ?

Link is dead. Can I get the fix?

Using Windows 10

The mentioned test build you refer to is outdated is six month old and was meant to test a possible fix for the inital problem.
A fix was released with client version 3.12.3.