<![CDATA[QtCreator freezes von Ubuntu 26.04 after canceling the build]]>I'm having an annoying problem here. I'm mostly developing in Windows using Visual Studio, but I also provide Linux builds of my application. I was using an XUbuntu 22 up to now.

I'm doing that in a Virtual Box VM.

Now I'm trying to migrate to Ubuntu 26.04. It works, I can build and run the application, but when I cancel a build the build stops and then QtCreator freezes.

And it freezes to a degree where I cannot close it, cannot kill it (neither -9 nor SIGKILL). I cannot even reboot the VM. I have to kill all Virtual Box processes in the Windows task manager.

I found no solution for that.

I tried both LUbuntu and XUbuntu. After a while, the OS says the window is busy and not responding and offers to close it. But it won't resume work after restarting. It hangs at "Loading Session".

Probably because the build processes are all still there:

2970  0.0  0.0   9904  3492 ?        D    22:39   0:00 g++ -c -pipe -g -Wall -Wextra -Wno-unused-parameter -Wno-unused-variable -D_REENTRANT -DQT_Q
2971  3.0 15.3 721628 615420 ?       D    22:39   0:03 /usr/libexec/gcc/x86_64-linux-gnu/15/cc1plus -quiet -I ../../../MyProject -I . -I ../../../My
2972  0.0  0.1  11876  4440 ?        S    22:39   0:00 /bin/x86_64-linux-gnu-as -I ../../../MyMyProject -I . -I ../../../MyProject -I ../../../MyProject
2973  0.0  0.0   9904  3488 ?        D    22:39   0:00 g++ -c -pipe -g -Wall -Wextra -Wno-unused-parameter -Wno-unused-variable -D_REENTRANT -DQT_Q
2974  2.6 15.4 725892 617020 ?       D    22:39   0:03 /usr/libexec/gcc/x86_64-linux-gnu/15/cc1plus -quiet -I ../../../MyProject -I . -I ../../../My
2975  0.0  0.1  11876  4468 ?        S    22:39   0:00 /bin/x86_64-linux-gnu-as -I ../../../MyProject -I . -I ../../../MyProject -I ../../../MyProject
2976  0.0  0.0   9904  3488 ?        D    22:39   0:00 g++ -c -pipe -g -Wall -Wextra -Wno-unused-parameter -Wno-unused-variable -D_REENTRANT -DQT_Q
2977  0.1  0.5  68732 22992 ?        D    22:39   0:00 /usr/libexec/gcc/x86_64-linux-gnu/15/cc1plus -quiet -I ../../../MyProject -I . -I ../../../Myi
2978  0.0  0.1  11876  4364 ?        S    22:39   0:00 /bin/x86_64-linux-gnu-as -I ../../../MyProject -I . -I ../../../MyProject -I ../../../MyProject
2979  0.0  0.0   9904  3488 ?        D    22:39   0:00 g++ -c -pipe -g -Wall -Wextra -Wno-unused-parameter -Wno-unused-variable -D_REENTRANT -DQT_Q
2980  0.0  0.5  68404 21552 ?        D    22:39   0:00 /usr/libexec/gcc/x86_64-linux-gnu/15/cc1plus -quiet -I ../../../MyProject -I . -I ../../../My
2981  0.0  0.1  11876  4464 ?        S    22:39   0:00 /bin/x86_64-linux-gnu-as -I ../../../MyProject -I . -I ../../../MyProject -I ../../../MyProject

Probably QtCreator couldn't kill them either.

I'm using QtCretor 18.0.2 Based on Qt 6.10.2 (GCC 15.2.0, x86_64)

What has to be changed so that QtCreator properly kills all those processes upon cancelling a build?

]]>https://forum.qt.io/topic/164856/qtcreator-freezes-von-ubuntu-26.04-after-canceling-the-buildRSS for NodeWed, 30 Sep 2026 08:40:37 GMTSat, 04 Jul 2026 20:48:47 GMT60<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Wed, 19 Aug 2026 19:08:40 GMT]]>I moved the output folder to a local folder inside the VM. That seems to solve the problem. Only issue now is that when I run a build the Build Settings right beneath "Build directory" say: "The Makefile is for a different project. The build will be overwritten"

This is only for the active build. When I change from debug to release, the message disappears in debug and appears in release and vice versa.

It won't go away when I specify a full absolute path to somewhere in the local file system.

It's bit strange, because Debug and Release builds are compiled into different folders without problem. Nothing is overwritten.

]]>https://forum.qt.io/post/839792https://forum.qt.io/post/839792Wed, 19 Aug 2026 19:08:40 GMT<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Thu, 06 Aug 2026 06:35:01 GMT]]>Upgrade to QtCreator 19+ with the known fix, or move the build folder from a shared folder (vboxsf) to a local disk (ext4) inside the virtual machine, perhaps because the problem is related to I/O against a shared folder with Windows, and not to the QtCreator version itself.

]]>https://forum.qt.io/post/839546https://forum.qt.io/post/839546Thu, 06 Aug 2026 06:35:01 GMT<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Thu, 06 Aug 2026 05:03:05 GMT]]>@berliner said in QtCreator freezes von Ubuntu 26.04 after canceling the build:

Could it be a problem that I'm compiling to folder shared with the windows host?

Is it a network drive?
Did you try on a local partition with a Linux file system?

]]>https://forum.qt.io/post/839545https://forum.qt.io/post/839545Thu, 06 Aug 2026 05:03:05 GMT<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Wed, 05 Aug 2026 21:47:18 GMT]]>I tried QtCreator 19.0.2, Qt 6.11.1, CMake 3.30.5 on XUbuntu 24. There the "Enabling the "Solid-state Drive (SSD)" didn't fix it either. Compiler is set to "GCC (C++, x86 64 bit at /usr/bin/g++)".

ps aux still shows me all those hanging g++ processes.

Still have to try on XUbuntu 26 again where "Enabling the "Solid-state Drive (SSD)" had improved the situation. But did obviously not on XUbuntu 24.

Could it be a problem that I'm compiling to folder shared with the windows host?

]]>https://forum.qt.io/post/839544https://forum.qt.io/post/839544Wed, 05 Aug 2026 21:47:18 GMT<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Mon, 20 Jul 2026 09:46:32 GMT]]>@berliner : It was fixed in https://codereview.qt-project.org/c/qt-creator/qt-creator/+/708134 commit. However, it went to Creator 19.0 so please try this version to verify whether it fixes your issue.

]]>https://forum.qt.io/post/839240https://forum.qt.io/post/839240Mon, 20 Jul 2026 09:46:32 GMT<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Thu, 16 Jul 2026 20:05:36 GMT]]>Gemini told me to go to the VM settings and set the VDI to "SSD drive" in the SATA Controller. This has helped.

The explanation is:

"Enabling the "Solid-state Drive (SSD)" option tells the Xubuntu kernel that the virtual drive has no mechanical seek times. As a result, Linux drastically optimizes its write queues (I/O scheduler) and immediately aborts aborted compiler write operations instead of letting them starve in a deadlock loop (D-state)."

It still sounds like Ubuntu is somehow messing up if that is really a solution.

I also noted the problem with an old XUbuntu 22 guest, which didn't have that problem before when running from older versions of Virtual Box. So, perhaps it's a problem of current Virtual Box 7.12. together with XUbuntu.

]]>https://forum.qt.io/post/839188https://forum.qt.io/post/839188Thu, 16 Jul 2026 20:05:36 GMT<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Tue, 14 Jul 2026 18:33:04 GMT]]>The same on XUbuntu 24 with QtCreator 13.0.0 and Qt 6.4.2

]]>https://forum.qt.io/post/839155https://forum.qt.io/post/839155Tue, 14 Jul 2026 18:33:04 GMT<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Tue, 07 Jul 2026 19:30:06 GMT]]>@SGaist

I installed QtCreator 20.0.0, but unfortunately the problem is the same.

]]>https://forum.qt.io/post/839043https://forum.qt.io/post/839043Tue, 07 Jul 2026 19:30:06 GMT<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Mon, 06 Jul 2026 19:03:32 GMT]]>I remember there was a post not long ago with similar symptoms. Can you try a more recent version of Qt Crestor ?

]]>https://forum.qt.io/post/839032https://forum.qt.io/post/839032Mon, 06 Jul 2026 19:03:32 GMT<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Sun, 05 Jul 2026 21:35:59 GMT]]>@SGaist

It's set to 4 (-j4), but setting it to 1 doesn't help.

]]>https://forum.qt.io/post/839018https://forum.qt.io/post/839018Sun, 05 Jul 2026 21:35:59 GMT<![CDATA[Reply to QtCreator freezes von Ubuntu 26.04 after canceling the build on Sun, 05 Jul 2026 18:50:30 GMT]]>Hi and welcome to devnet,

Are you handling the number of jobs yourself ?
If so, how many are you starting in parallel ?

]]>https://forum.qt.io/post/839017https://forum.qt.io/post/839017Sun, 05 Jul 2026 18:50:30 GMT