[2026.4.0 Regression] BlockingScheduler scripts exit silently with no output when run via F5

[TwanisMae-EViG]

Type: Bug

Behaviour

BlockingScheduler scripts exit silently with no output when run via F5

Steps to reproduce:

1. Install Python extension version 2026.4.0
2. Open a Python script using APScheduler BlockingScheduler with sched.start() inside if name == 'main'
3. Press F5 to run
4. Script exits instantly with no output and no error

Extension version: 2026.4.0
VS Code version: Code 1.118.1 (034f571df509819cc10b0c8129f66ef77a542f0e, 2026-04-29T17:36:44+03:00)
OS version: Windows_NT x64 10.0.20348
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.13.3
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): System
• Value of the python.languageServer setting: Default

User Settings

languageServer: "Pylance"

terminal
• executeInFileDir: "<placeholder>"

Installed Extensions

Extension Name	Extension Id	Version
debugpy	ms-	2026.4.0
js-debug	ms-	1.117.0
js-debug-companion	ms-	1.1.3
jsts-chat-features	Typ	0.0.2
python	ms-	2026.4.0
rainbow-csv	mec	3.24.1
vscode-js-profile-table	ms-	1.0.10
vscode-pylance	ms-	2026.2.1
vscode-python-envs	ms-	1.28.0

[eleanorjboyd]

Thanks for the detailed report! I'll look into what changed in 2026.4.0 that could affect long-running/blocking scripts launched via F5.

One quick question to help narrow this down: are you using a custom launch.json configuration, or are you relying on the default debug configuration (i.e. no launch.json in your .vscode folder)?

If you do have a launch.json, could you share its contents? This will help us confirm whether the regression is in how the default launch config is generated or in the debugger attach behavior itself.

In the meantime, a potential workaround to try: add "subProcess": true to your launch.json configuration if you don't already have one — APScheduler's BlockingScheduler can spawn subprocesses that the debugger may be interrupting.

[TwanisMae-EViG]

Hi Eleanor,Thank you for the quick response!As an FYI, I had rolled back Pylance and added a launch.json (I wasn't using one prior), and believed this had resolved the issue. However, when I went to test your suggestions I discovered the root cause was actually in the Python Debugger extension, not Pylance:• 2026.5.11171013 is the confirmed broken version• 2026.6.0 (or the latest pre-release) appears to resolve itI was able to reproduce the issue consistently on the broken version, and it looks like the fix was pushed while I was working through the workarounds.I believe we can close this ticket as resolved.Thank you!Steven JohnsonOn May 1, 2026, at 12:05 PM, Eleanor Boyd ***@***.***> wrote:eleanorjboyd left a comment (microsoft/vscode-python#25944) Thanks for the detailed report! I'll look into what changed in 2026.4.0 that could affect long-running/blocking scripts launched via F5. One quick question to help narrow this down: are you using a custom launch.json configuration, or are you relying on the default debug configuration (i.e. no launch.json in your .vscode folder)? If you do have a launch.json, could you share its contents? This will help us confirm whether the regression is in how the default launch config is generated or in the debugger attach behavior itself. In the meantime, a potential workaround to try: add "subProcess": true to your launch.json configuration if you don't already have one — APScheduler's BlockingScheduler can spawn subprocesses that the debugger may be interrupting. —Reply to this email directly, view it on GitHub, or unsubscribe.Triage notifications on the go with GitHub Mobile for iOS or Android. You are receiving this because you authored the thread.Message ID: ***@***.***>