ChimeraX not starting on Windows Server 2016

[juergen.eirich@…]

Hi,

 

I tried installing ChimeraX 1.10.1 (as well as the 27. Aug. 2025 daily) on a
Windows Server 2016 64 bit system, with default settings of the setup.

 

The GUI does not start. When trying to start the console, I get the error
pasted below.

 

Python 3.11.4 is starting from the respective ChimeraX bin folder,
C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-packages\PyQt6\Qt6\bin seems
to contain the respective DLLs.

 

Do you have any hints on what might be wrong with PyQt6.QtCore?

 

Best

 

Jürgen

 

 

 

NOTE: Traceback (most recent call last):

  File "<frozen runpy>", line 198, in _run_module_as_main

  File "<frozen runpy>", line 88, in _run_code

  File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-

packages\chimerax\core\\__main__.py", line 1220, in <module>

    exit_code = init(sys.argv)

                ^^^^^^^^^^^^^^

  File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-

packages\chimerax\core\\__main__.py", line 691, in init

    from chimerax.ui import initialize_qt

  File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-

packages\chimerax\ui\\__init__.py", line 21, in <module>

    from .gui import MainToolWindow, initialize_qt, menu_capitalize,

tool_user_error

  File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-

packages\chimerax\ui\gui.py", line 29, in <module>

    from Qt.QtWidgets import QApplication

  File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-

packages\Qt\\__init__.py", line 69, in <module>

    from PyQt6.QtCore import PYQT_VERSION_STR as PYQT6_VERSION

ImportError: DLL load failed while importing QtCore: The specified procedure

could not be found.

 

 

BUG: ImportError: DLL load failed while importing QtCore: The specified
procedure

could not be found.

 

File "C:\Program Files\ChimeraX
1.10.1\bin\Lib\site-packages\Qt\\__init__.py",

line 69, in

from PyQt6.QtCore import PYQT_VERSION_STR as PYQT6_VERSION

 

_See log for complete Python traceback._

 

 

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[juergen.eirich@…]

Added by email2trac

[Greg Couch]

From that error, it appears that the Qt user interface toolkit, that ChimeraX uses, no longer supports that version of Windows. I found that Windows Server 2016 is based on Windows 10 build 1511, and ​https://doc.qt.io/qt-6/supported-platforms.html#windows says that Qt requires Window 10 build 1809 or newer. So you'll need to upgrade your system to run ChimeraX.