[Solved] QCAD not running since Qt 6.12

knille · 2026-10-14 21:29:44

For me the 2D CAD tool QCAD is not starting anymore since update of Qt from 6.11 to 6.12. I someone knows if this can be fixed, please let me know. Right now i stay with Qt 6.11.

Last edited by knille (Today 07:29:44)

SimonJ · Yesterday 02:42:57

After installing the new QT have you rebuilt the application?

seth · Yesterday 03:32:04

Not if they're using https://archlinux.org/packages/extra/x86_64/qcad/
"QT" is btw. Apple QuickTime - POSIX is case sensitive

@knille, please don't paraphrase, https://bbs.archlinux.org/viewtopic.php?id=57855
It probably not-started w/ an error/crash or backtrace which might be useful information (there was some fuzz about qt6-webengine that might remain an open issue but afaict qcad does not depend on that)

mpan · Yesterday 03:42:49

QCAD is an official package (extra/qcad). A user shouldn’t need to rebuild it in the normal course of using Arch.

The user isn’t paraphrasing. QCAD quits cleanly, instantly after being started. Yes: quits cleanly. The program doesn’t crash. Exit status is 0, no error messages, the last syscall is `exit_group(0)`, all children also exit with 0.

Rebuilding extra/qcad with a fully updated system (sans kernel) right now to see how it goes. (TBC…)

Last edited by mpan (Yesterday 03:43:28)

seth · Yesterday 03:54:42

"not starting anymore" != "the last syscall is `exit_group(0)`"
Are there also no complaints about missing plugins or other messages?

https://archlinux.org/packages/extra/x8 … 6-5compat/ still has a shocking amount of consumers so that's probably not it.

In case the rebuild doesn't cut it, does "qcad -allow-multiple-instances" still work?

arojas · Yesterday 06:36:03

Running the symlink target /usr/lib/qcad/qcad-bin directly works, so this is likely to be another manifestation of https://gitlab.archlinux.org/archlinux/ … 17c4e87fa2 (and therefore a packaging bug to be reported to the qcad package, since the symlinks are created at packaging time)

Last edited by arojas (Yesterday 06:36:48)

mpan · Yesterday 11:03:43

seth wrote:

Are there also no complaints about missing plugins or other messages?

Yes, but they are normal as far as I recall.⁽¹⁾ Nothing indicating a crash:

QCAD version 3.33.1
Warning: "Folder 'plugins' does not exist"
13:01:14: Debug: loading plugins...
Warning: RPluginLoader::getPluginsPath: No plugins directory found.
13:01:14: Debug: loading static plugins...
Warning: No script handler found...
Warning: RPluginLoader::getPluginsPath: No plugins directory found.

seth wrote:

In case the rebuild doesn't cut it, does "qcad -allow-multiple-instances" still work?

Since the building still continues, I tried that in meantime. Same effect.

I also tested what arojas said. Indeed, starting this binary directly leads to QCAD starting. I didn’t test it beyond the welcome screen.

All tests performed with no previous QCAD config/cache/data files.
____
⁽¹⁾ I’m not a QCAD user. Just trying to help to debug the situation. I did test it among other CAD tools earlier this year, though.

seth · Yesterday 12:13:19

Seen arojas' post? Sounds spot on.

knille · Yesterday 15:29:23

thx for your help everyone. especially arojas. i can confirm that executing /usr/bin/qcad/qcad-bin starts the application normally.

could someone file a bug report for the package on the arch gitlab? i created an account there few days ago but it wasn't whitelisted so far.

mpan · Yesterday 17:38:54

Rebuilding with the current PKGBUILD doesn’t affect the issue.

Running the official version with Qt 6.11 indeed allows it to start. The rebuilt one does not.

I was incorrect regarding the messages produced. I remembered it wrong, the warnings are different for when QCAD starts:

QCAD version 3.33.1
19:31:56: Debug: loading plugins...
19:31:58: Debug: RJSApiPlugin::init
19:31:58: Debug: loading static plugins...
Warning: Unimplemented code.
Warning: Unimplemented code.
Warning: Unimplemented code.
Warning: Unimplemented code.
Warning: Unimplemented code.
Warning: Unimplemented code.
Warning: QWidget_Wrapper::castToBase: type not found: "RMainWindowQt"
Warning: Unimplemented code.
Warning: Unimplemented code.
Warning: Unimplemented code.
Warning: Unimplemented code.
Warning: Unimplemented code.

While the reason is obvious, for formality, the version rebuilt against Qt 6.12 fails with:

qcad: /usr/lib/libQt6Core.so.6: version `Qt_6.12' not found (required by qcad)
qcad: /usr/lib/libQt6Core.so.6: version `Qt_6.12' not found (required by /usr/lib/qcad/libqcadentity.so)
qcad: /usr/lib/libQt6Core.so.6: version `Qt_6.12' not found (required by /usr/lib/qcad/libqcadcore.so)

seth · Yesterday 18:22:32

@knille, https://gitlab.archlinux.org/archlinux/ … k_items/11

knille · Today 07:28:59

great, thank you seth! there's already the new qcad package 3.33.1.0-2 out that fixes the problem.

Arch Linux

#1 2026-10-14 21:29:44

[Solved] QCAD not running since Qt 6.12

#2 Yesterday 02:42:57

Re: [Solved] QCAD not running since Qt 6.12

#3 Yesterday 03:32:04

Re: [Solved] QCAD not running since Qt 6.12

#4 Yesterday 03:42:49

Re: [Solved] QCAD not running since Qt 6.12

#5 Yesterday 03:54:42

Re: [Solved] QCAD not running since Qt 6.12

#6 Yesterday 06:36:03

Re: [Solved] QCAD not running since Qt 6.12

#7 Yesterday 11:03:43

Re: [Solved] QCAD not running since Qt 6.12

#8 Yesterday 12:13:19

Re: [Solved] QCAD not running since Qt 6.12

#9 Yesterday 15:29:23

Re: [Solved] QCAD not running since Qt 6.12

#10 Yesterday 17:38:54

Re: [Solved] QCAD not running since Qt 6.12

#11 Yesterday 18:22:32

Re: [Solved] QCAD not running since Qt 6.12

#12 Today 07:28:59

Re: [Solved] QCAD not running since Qt 6.12

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