ATTN: Windows Sigil users

DiapDealer · 09-16-2025, 10:06 AM

It appears that newer and newer versions of Qt/Sigil (and Visual Studio) may require you to update you Microsoft Visual C++ 2015-2022 Redistributable (x64) runtime.

I just had a failure to launch on an older laptop with a beta version of Sigil using Qt6.9.2. No error, just no launch. Updating the redistributable fixed the problem. Damn Microsoft! These things are supposed to be forward/backward compatible (and they have been for quite a long time), but it looks like something is starting to fall through the cracks. Sigil requires the x64 version of the runtime (in case you don't use both x86 and x64).

Version 14.40.33816 of the redistributable was not good enough on my machine. The latest version of 14.44 restored all functionality.

So head this issue off at the pass and update those runtimes! At the very least, keep this post in mind if Sigil stops launching for you. And spread the word so we can hopefully keep ahead of this!

https://learn.microsoft.com/en-us/cp...?view=msvc-170

POST DATE: 16 September 2025

JSWolf · 09-16-2025, 12:11 PM

Quote:

Originally Posted by DiapDealer

It appears that newer and newer versions of Qt/Sigil (and Visual Studio) may require you to update you Microsoft Visual C++ 2015-2022 Redistributable (x64) runtime.

I just had a failure to launch on an older laptop with a beta version of Sigil using Qt6.9.2. No error, just no launch. Updating the redistributable fixed the problem. Damn Microsoft! These things are supposed to be forward/backward compatible (and they have been for quite a long time), but it looks like something is starting to fall through the cracks. Sigil requires the x64 version of the runtime (in case you don't use both x86 and x64).

Version 14.40.33816 of the redistributable was not good enough on my machine. The latest version of 14.44 restored all functionality.

So head this issue off at the pass and update those runtimes! At the very least, keep this post in mind if Sigil stops launching for you. And spread the word so we can hopefully keep ahead of this!

https://learn.microsoft.com/en-us/cp...?view=msvc-170

POST DATE: 16 September 2025

This is my suggestion.

When you do release Sigil with Qt 6.9.2 or later, put this info up on the website with a link to get the version Microsoft Visual Runtime that allows Sigil to work.

DiapDealer · 09-16-2025, 12:25 PM

Quote:

Originally Posted by JSWolf

This is my suggestion.

When you do release Sigil with Qt 6.9.2 or later, put this info up on the website with a link to get the version Microsoft Visual Runtime that allows Sigil to work.

I'll put something on the website, but I'm going to do it long before the next release. That will be way too late to head off any of the slew of bug reports that would result. Most people don't even look at release announcements. They go straight for the download.

More eyes here at Mobileread means more help setting people straight.

JSWolf · 09-16-2025, 12:40 PM

Quote:

Originally Posted by DiapDealer

I'll put something on the website, but I'm going to do it long before the next release. That will be way too late to head off any of the slew of bug reports that would result. Most people don't even look at release announcements. They go straight for the download.

More eyes here at Mobileread means more help setting people straight.

That's a good idea.

Doitsu · 09-16-2025, 01:08 PM

Quote:

Originally Posted by DiapDealer

Version 14.40.33816 of the redistributable was not good enough on my machine. The latest version of 14.44 restored all functionality.

FYI: I installed Sigil 2.6.2 today and had no problems starting Sigil.

The runtime version numbers are:
C:\Windows\System32\msvcp140.dll: 14.38.32919.0
C:\Windows\System32\vcruntime140.dll 14.38.32919.0

Can't you simply bundle the runtime installer for the latest version when you release the next Sigil version?

DiapDealer · 09-16-2025, 01:16 PM

Sigil 2.6.2 is fine. It's still using Qt6.8.2. That version ran fine on the same machine I was testing on too. It wasn't until I installed a beta build of Sigil with Qt6.9.2 that my version of the runtime was insufficient.

I will say that it was a CI-built version of Sigil, so it's entirely possible it was the version of Visual Studio used to compile Sigil that caused the problem. But the fact of the matter is: the version of Visual Studio installed on github's action runner images is eventually going to be the version I use to make Sigil release builds on my local machine. So it's still only a matter of time before it becomes a factor.

DNSB · 09-16-2025, 05:49 PM

On my computer, the 14.44.35211.0 update was already installed. From the install date, it seems to have been included in the VS 2022 ver. 17.14.8 security update installed in early July.

philja · 09-16-2025, 06:10 PM

I upgraded my W10 machine to Windows 11 a few weeks ago and I've kept it up to date since. It identifies itself as Windows 11 Pro 24H2

When I just checked, vcruntime140.dll is at version 14.42.34438.0 and carries a modification date of 1 Feb 2002.

So it looks like only very old machines would be affected by having earlier versions of this file.

DiapDealer · 09-16-2025, 08:20 PM

Quote:

Originally Posted by philja

I upgraded my W10 machine to Windows 11 a few weeks ago and I've kept it up to date since. It identifies itself as Windows 11 Pro 24H2

When I just checked, vcruntime140.dll is at version 14.42.34438.0 and carries a modification date of 1 Feb 2002.

So it looks like only very old machines would be affected by having earlier versions of this file.

I'm not sure why you're seeing that particular modification date, but version 14.42.34438 of the VC++ runtime was released in March 2025.

Does Windows 11 keep those redistributables updated with Windows Update? I know they didn't with Windows 10. I think it's still up to the user to manually update those.

Capricorn · 09-17-2025, 02:52 AM

I asked Copilot about these updates and got the follwing answer:
How Microsoft Visual C++ Redistributables Are Updated
- Windows Update can deliver updates to Visual C++ Redistributables—especially if they're bundled with system updates or required by Windows components.
- However, not all redistributable updates are pushed via Windows Update. Many updates—especially newer versions like those for Visual Studio 2015–2022—are released independently and must be downloaded manually or installed by applications that include them.

In short sometimes yes, most of the time no.

BeckyEbook · 09-17-2025, 07:23 AM

Yesterday, I built a new Sigil with Qt6.9.2, including building the installer, but Sigil won't start. Today, I made further attempts, but still without success. Each time, Sigil builds without errors, but it just won't start.

* Windows 10 Pro 22H2
* Visual Studio 2022 17.14.15 (September 2025)
* VCTools 14.44.35207
* VCRedist 14.44.35112

From log (events):

Spoiler:

This line is probably key:
Path of the module causing the error: C:\Program Files\Sigil\Qt6WebEngineCore.dll

What else can I do/check/debug?

KevinH · 09-17-2025, 10:05 AM

Did you mean what you wrote ...

VCRedist 14.44.35112

Or did you mean the latest version:

VCRedist 14.44.35211

Do you have the WinDBG debugger installed? If so you can try enabling a crashdump and running the WinDbg debugger to get a backtrace from it so we can see where in Sigil's code this call to QWebEngineCore is happening.

Did you compile Qt 6.9.2 itself with our patches or are you using the official Qt 6.9.2 binaries direct from Qt?

DiapDealer · 09-17-2025, 11:01 AM

I know QtWebEngine for Qt6.9.2 requires a newer version of the Windows SDK (a Visual Studio component) to build on Windows than 6.8.2 did. I don't know if that means building Sigil against that newer dll will require the same SDK or not, but it's worth a shot (if you're using my recently patched/built Qt6.9.2)

Make sure your Visual Studio is using the Windows 11 SDK version 10.0.26100.0 when building Sigil.

That's about the only thing I can think of. But I'm also pretty certain I've built Sigil with 6.9.2 on my Windows 10 machine with an older version of Visual Studio with no trouble. I'll do some double-checking.

BeckyEbook · 09-17-2025, 11:41 AM

@KevinH:
C:\Windows\System32\vcruntime140.dll 14.44.35211.0

My previous versions are from environment variables:

Code:

VCToolsInstallDir=C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\
VCToolsRedistDir=C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Redist\MSVC\14.44.35112\
VCToolsVersion=14.44.35207
VisualStudioVersion=17.0
VS170COMNTOOLS=C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\Tools\
VSCMD_ARG_app_plat=Desktop
VSCMD_ARG_HOST_ARCH=x64
VSCMD_ARG_TGT_ARCH=x64
VSCMD_ARG_VCVARS_VER=14.44
VSCMD_VER=17.14.15

Unfortunately, I don't have WinDBG because my previous attempts have never been successful. Not the installation itself, but its subsequent operation. So I'll wait with it, maybe there will be another solution.

Qt 6.9.2 from DiapDealer: Qt6.9.2ci_x64_VS2022.7z

@DiapDealer:
Yes, I have Qt 6.9.2 from your GitHub.

I'll install the SDK again, even though I thought I had the latest version.

I'll keep trying, maybe I'll find something else.

DiapDealer · 09-17-2025, 12:10 PM

OK. I can confirm that I'm able to compile Sigil on Windows 10 with a much older version of Visual Studio (no newer Windows 11 SDK installed) than the one I used to compile Qt6.9.2 and it runs just fine on my Windows VM (even with a much older version of the VC++ redist). And I can run it fine on a physical Windows 10 laptop.

I can also download the ci-built version of Sigil (built with a much newer version of Visual Studio--but the same Qt6.9.2 I used in my local build), and it also runs fine on the same Windows 10 laptop (but needs the newer V++ redist).

The version of Qt6.9.2 I'm building Sigil with is available here: https://github.com/dougmassay/win-qt...s/tag/v5.212-1 It's named Qt6.9.2ci_x64_VS2022.7z EDIT: nevermind, it looks like that's what you're using already.

I also made sure I'm not setting any special environment variables that might affect the way Sigil runs/launches.

So unless there's something missing or misconfigured (or buggy) with your precise version of Visual Studio, I'm not certain what might be going wrong for you.

09-16-2025, 10:06 AM	#1
DiapDealer Grand Sorcerer Posts: 28,897 Karma: 207182180 Join Date: Jan 2010 Device: Nexus 7, Kindle Fire HD	ATTN: Windows Sigil users It appears that newer and newer versions of Qt/Sigil (and Visual Studio) may require you to update you Microsoft Visual C++ 2015-2022 Redistributable (x64) runtime. I just had a failure to launch on an older laptop with a beta version of Sigil using Qt6.9.2. No error, just no launch. Updating the redistributable fixed the problem. Damn Microsoft! These things are supposed to be forward/backward compatible (and they have been for quite a long time), but it looks like something is starting to fall through the cracks. Sigil requires the x64 version of the runtime (in case you don't use both x86 and x64). Version 14.40.33816 of the redistributable was not good enough on my machine. The latest version of 14.44 restored all functionality. So head this issue off at the pass and update those runtimes! At the very least, keep this post in mind if Sigil stops launching for you. And spread the word so we can hopefully keep ahead of this! https://learn.microsoft.com/en-us/cp...?view=msvc-170 POST DATE: 16 September 2025 Last edited by DiapDealer; 09-16-2025 at 11:02 AM.

09-16-2025, 01:16 PM	#6
DiapDealer Grand Sorcerer Posts: 28,897 Karma: 207182180 Join Date: Jan 2010 Device: Nexus 7, Kindle Fire HD	Sigil 2.6.2 is fine. It's still using Qt6.8.2. That version ran fine on the same machine I was testing on too. It wasn't until I installed a beta build of Sigil with Qt6.9.2 that my version of the runtime was insufficient. I will say that it was a CI-built version of Sigil, so it's entirely possible it was the version of Visual Studio used to compile Sigil that caused the problem. But the fact of the matter is: the version of Visual Studio installed on github's action runner images is eventually going to be the version I use to make Sigil release builds on my local machine. So it's still only a matter of time before it becomes a factor. Last edited by DiapDealer; 09-16-2025 at 01:21 PM.

09-17-2025, 11:41 AM	#14
BeckyEbook Guru Posts: 900 Karma: 3501166 Join Date: Jan 2017 Location: Poland Device: Various	@KevinH: C:\Windows\System32\vcruntime140.dll 14.44.35211.0 My previous versions are from environment variables: Code: VCToolsInstallDir=C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\ VCToolsRedistDir=C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Redist\MSVC\14.44.35112\ VCToolsVersion=14.44.35207 VisualStudioVersion=17.0 VS170COMNTOOLS=C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\Tools\ VSCMD_ARG_app_plat=Desktop VSCMD_ARG_HOST_ARCH=x64 VSCMD_ARG_TGT_ARCH=x64 VSCMD_ARG_VCVARS_VER=14.44 VSCMD_VER=17.14.15 Unfortunately, I don't have WinDBG because my previous attempts have never been successful. Not the installation itself, but its subsequent operation. So I'll wait with it, maybe there will be another solution. Qt 6.9.2 from DiapDealer: Qt6.9.2ci_x64_VS2022.7z @DiapDealer: Yes, I have Qt 6.9.2 from your GitHub. I'll install the SDK again, even though I thought I had the latest version. I'll keep trying, maybe I'll find something else.

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09-16-2025, 05:49 PM	#7
DNSB Bibliophagist Posts: 48,265 Karma: 174315444 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	On my computer, the 14.44.35211.0 update was already installed. From the install date, it seems to have been included in the VS 2022 ver. 17.14.8 security update installed in early July.

09-16-2025, 06:10 PM	#8
philja Addict Posts: 306 Karma: 516 Join Date: Nov 2015 Location: Europe EEC Device: Kindle Fire HD6 & HD8	I upgraded my W10 machine to Windows 11 a few weeks ago and I've kept it up to date since. It identifies itself as Windows 11 Pro 24H2 When I just checked, vcruntime140.dll is at version 14.42.34438.0 and carries a modification date of 1 Feb 2002. So it looks like only very old machines would be affected by having earlier versions of this file.

09-17-2025, 02:52 AM	#10
Capricorn Belgian Pommes Frites Posts: 131 Karma: 35038 Join Date: Jan 2012 Device: Pocketbook Touch HD	I asked Copilot about these updates and got the follwing answer: How Microsoft Visual C++ Redistributables Are Updated - Windows Update can deliver updates to Visual C++ Redistributables—especially if they're bundled with system updates or required by Windows components. - However, not all redistributable updates are pushed via Windows Update. Many updates—especially newer versions like those for Visual Studio 2015–2022—are released independently and must be downloaded manually or installed by applications that include them. In short sometimes yes, most of the time no.

09-17-2025, 10:05 AM	#12
KevinH Sigil Developer Posts: 9,073 Karma: 6361556 Join Date: Nov 2009 Device: many	Did you mean what you wrote ... VCRedist 14.44.35112 Or did you mean the latest version: VCRedist 14.44.35211 Do you have the WinDBG debugger installed? If so you can try enabling a crashdump and running the WinDbg debugger to get a backtrace from it so we can see where in Sigil's code this call to QWebEngineCore is happening. Did you compile Qt 6.9.2 itself with our patches or are you using the official Qt 6.9.2 binaries direct from Qt?

09-17-2025, 11:01 AM	#13
DiapDealer Grand Sorcerer Posts: 28,897 Karma: 207182180 Join Date: Jan 2010 Device: Nexus 7, Kindle Fire HD	I know QtWebEngine for Qt6.9.2 requires a newer version of the Windows SDK (a Visual Studio component) to build on Windows than 6.8.2 did. I don't know if that means building Sigil against that newer dll will require the same SDK or not, but it's worth a shot (if you're using my recently patched/built Qt6.9.2) Make sure your Visual Studio is using the Windows 11 SDK version 10.0.26100.0 when building Sigil. That's about the only thing I can think of. But I'm also pretty certain I've built Sigil with 6.9.2 on my Windows 10 machine with an older version of Visual Studio with no trouble. I'll do some double-checking.

09-17-2025, 12:10 PM	#15
DiapDealer Grand Sorcerer Posts: 28,897 Karma: 207182180 Join Date: Jan 2010 Device: Nexus 7, Kindle Fire HD	OK. I can confirm that I'm able to compile Sigil on Windows 10 with a much older version of Visual Studio (no newer Windows 11 SDK installed) than the one I used to compile Qt6.9.2 and it runs just fine on my Windows VM (even with a much older version of the VC++ redist). And I can run it fine on a physical Windows 10 laptop. I can also download the ci-built version of Sigil (built with a much newer version of Visual Studio--but the same Qt6.9.2 I used in my local build), and it also runs fine on the same Windows 10 laptop (but needs the newer V++ redist). The version of Qt6.9.2 I'm building Sigil with is available here: https://github.com/dougmassay/win-qt...s/tag/v5.212-1 It's named Qt6.9.2ci_x64_VS2022.7z EDIT: nevermind, it looks like that's what you're using already. I also made sure I'm not setting any special environment variables that might affect the way Sigil runs/launches. So unless there's something missing or misconfigured (or buggy) with your precise version of Visual Studio, I'm not certain what might be going wrong for you.

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