Spyder closes silently at startup since 6.1.4 on WinPython; 6.1.3 works with the same environment

On Windows with WinPython, Spyder starts normally, displays its main window for a few seconds and then closes silently.

There is no traceback or error message in the command prompt.

The issue appears to have been introduced between Spyder 6.1.3 and 6.1.4.

I can reproduce the problem across several WinPython releases:

WinPython 3.13.12.0 + Spyder 6.1.3: works WinPython 3.13.13.0 + Spyder 6.1.4: fails WinPython 3.13.15.1 + Spyder 6.1.6: fails WinPython 3.13.15.1 + Spyder 6.1.7: fails WinPython 3.13.15.1 + Spyder 6.1.3: works

Therefore, the problem does not seem to be caused by the Python or WinPython version itself.

Steps to reproduce

With WinPython 3.13.15.1:

python -m pip install "spyder==6.1.7" spyder --new-instance

Spyder opens and then closes after a few seconds without any traceback.

Downgrading only Spyder fixes the issue:

python -m pip install "spyder==6.1.3" spyder --new-instance

Spyder then remains open and works normally.

Important observation: safe mode

With Spyder 6.1.6:

spyder --safe-mode

works: Spyder remains open.

However, using a fresh configuration directory does not solve the problem:

spyder --conf-dir "%TEMP%\spyder-test-616" --new-instance

still causes Spyder to close.

The same happens with another new configuration directory on another drive.

Removing SPYDER_CONFDIR also does not solve it:

set SPYDER_CONFDIR= spyder --new-instance

Spyder still closes.

Therefore, the difference between normal startup and --safe-mode seems relevant and does not appear to be simply caused by the Spyder configuration directory.

Dependencies

The following environment works correctly when Spyder is downgraded to 6.1.3:

Spyder 6.1.3 spyder-kernels 3.1.6 qtconsole 5.7.2 IPython 9.15.0 ipykernel 6.31.0 Python 3.13.15

This is important because the recent versions of spyder-kernels, qtconsole, IPython and ipykernel work correctly with Spyder 6.1.3 in exactly the same WinPython installation.

Additional tests

Matplotlib and PyQt work correctly outside Spyder:

python -X faulthandler -c "from PyQt5.QtWidgets import QApplication; app=QApplication([]); print('QT OK'); import matplotlib; print('MATPLOTLIB OK'); import matplotlib.pyplot as plt; print('PYPLOT OK')"

Result:

QT OK MATPLOTLIB OK PYPLOT OK

QtConsole also works:

python -X faulthandler -c "from PyQt5.QtWidgets import QApplication; app=QApplication([]); import qtconsole; print('QTCONSOLE',qtconsole.version); from qtconsole.rich_jupyter_widget import RichJupyterWidget; w=RichJupyterWidget(); print('WIDGET OK')"

Result:

QTCONSOLE 5.7.2 WIDGET OK

NumPy and Matplotlib binary modules load successfully:

numpy 2.5.2 matplotlib 3.11.1 matplotlib.ft2font: OK matplotlib.pyplot: OK IPython history observation

The IPython history database was checked with:

PRAGMA integrity_check

and returned:

('ok',)

Renaming:

%USERPROFILE%.ipython\profile_default\history.sqlite

allowed Spyder 6.1.6 to start successfully in one test.

spyder_debug.txt

spyder_debug.txt

However, the problem was still reproduced with Spyder 6.1.7, whereas reverting Spyder itself to 6.1.3 consistently solves the problem.

This may indicate an interaction between changes introduced in Spyder 6.1.4+ and IPython console/history initialization.

Expected behavior

Spyder should remain open and start normally, as it does with Spyder 6.1.3.

Actual behavior

Spyder 6.1.4 and later opens for a few seconds and then the whole application terminates silently, with no traceback in the command prompt.

Additional information

I can provide a verbose spyder --debug-info verbose startup log. The log does not contain a Python exception or traceback before the process terminates. # #