Sigil won't launch on Windows

[Coconutt]

Hi, I'm a foreigner user so please understand my poor English skill.

I want to run Sigil on Windows 10, but it isn’t working.
I already tried installing Java,
running Windows Compatibility Troubleshooter in all available modes,
uninstalling and reinstalling Sigil,
and turning off my security programs.

But it still won’t launch!

At first, I installed version 2.6.0, then retried with 2.5.1, but neither worked.
There are no error messages—just nothing happens.

I'm using an iMac, and when I tried to install it on macOS, it worked.
But on Windows (Bootcamp), there’s no response.

Is there any solution to this issue?
This is really critical for me since it’s related to my job.
Please let me know how to fix it.

[DiapDealer]

Where did you get the information that installing Java might help with Sigil?

There has to be some mention of the issue in the Windows event viewer.

I have zero experience with dual-boot Mac setup with Windows 10 as an alternate OS. My only guess is that the graphics card is not compatible with Qt6.

[Coconutt]

I don't remember where I saw it, but it might have been on some Korean web page.

My graphics card is a Radeon Pro 570X.
If that’s the issue, how could it work on macOS?

By the way, if that’s the case, does it mean I can’t use Sigil on my computer?

[DiapDealer]

Originally Posted by Coconutt

I don't remember where I saw it, but it might have been on some Korean web page.

My graphics card is a Radeon Pro 570X.
If that’s the issue, how could it work on macOS?

Because Qt6 uses an entirely different accelerated graphics backend on Windows than it does on Mac. Do you have the latest drivers installed for the graphics card on the Windows side of things?

Originally Posted by Coconutt

By the way, if that’s the case, does it mean I can’t use Sigil on my computer?

Not to overstate the obvious, but you've already mentioned that Sigil works fine on the Mac. Epubs produced by Sigil on a Mac are identical to those produced by Sigil on Windows (or Linux for that matter)

[DiapDealer]

It sounds as if Bootcamp Assistant handles the Windows drivers side of things for the Mac's hardware. It may be possible that those drivers are simply incompatible with Qt6.8.2.

[KevinH]

Yes, for bootcamp to work, you need Bootcamp to install Apple's driver kit for Windows first which allows Windows to use macOS hardware.

If you have tried updating your graphics drivers on the Window side, then I am not sure what else can be done.

Using Sigil on the Mac side works. I have taken my older MacOS iMacs and installed Manjaro Linux on them with a KDE Plasma desktop and run Sigil and that works too.

So it must be the Bootcamp installed drivers. Try updating them.

[JSWolf]

Originally Posted by KevinH

Yes, for bootcamp to work, you need Bootcamp to install Apple's driver kit for Windows first which allows Windows to use macOS hardware.

If you have tried updating your graphics drivers on the Window side, then I am not sure what else can be done.

Using Sigil on the Mac side works. I have taken my older MacOS iMacs and installed Manjaro Linux on them with a KDE Plasma desktop and run Sigil and that works too.

So it must be the Bootcamp installed drivers. Try updating them.

Do you think these environment variables under Windows may help?

QT_OPENGL=software
QTWEBENGINE_CHROMIUM_FLAGS=--disable-gpu

[KevinH]

It is not just Preview that is not being shown but instead the full main wiindow that is not showing. So disabling the gpu acceleration would not help you to see Sigil's MainWindiw. Changing the backside graphics kit may help to opengl may help. But that would require setting the relevant RHI env variable.

Here is what Qt's docs say about there RHI environment variable:

QSG_RHI_BACKEND
possible values: vulkan, metal, opengl, d3d11, d3d12

Requests the specific RHI backend. By default the targeted graphics API is chosen based on the platform, unless overridden by this variable.

So you could try setting a QSG_RHI_BACKEND environment variable to "opengl" or try "d3d11" or try "d3d12" and restarting Sigil after each to see if which if any of those 3 possible setting help.

[Highroller]

Sometimes Sigil doesn’t need Java at all, so that step won’t help. Try installing the latest Microsoft Visual C++ Redistributable (both x86 and x64). Many people reported that fixed the “no launch” problem.

[DiapDealer]

Originally Posted by Highroller

Sometimes Sigil doesn’t need Java at all, so that step won’t help. Try installing the latest Microsoft Visual C++ Redistributable (both x86 and x64). Many people reported that fixed the “no launch” problem.

Sigil never needs Java. Ever. Some 3rd party plugins might require Java to run, but that's entirely different.

The redistributable is a good idea since Sigil's installer no longer provides it (but only the x64 version ... the x86 version will be of absolutely no help for the latest versions of Sigil). But Windows has always given me a visible indication when a required runtime is not available.

Also note that the minimum version of Windows that Sigil will run on (Windows 10 1809 since July of 2023) comes with the necessary redistributable preinstalled. So unless they were uninstalled for some reason... it should be there. That's why we no longer include the runtime installation as part of Sigil's installer in the first place.