Why is my command prompt freezing on Windows 10?

Question

I'm adding this question after spending an entire day wrestling with this incredibly frustrating feature of the Windows 10 command prompt which made me think there was something wrong with my console application code. I hope it will help someone.

Issue: My console application seems to randomly stop running. What is going on?

Answer 1

The issue ended up being a new feature of the windows 10 console. Under the default config, whenever you click on a command window in windows 10, it immediately halts the application process when it attempts to write to the console. When this happens, the command window has gone into "selection" mode.

You can tell it has happened because it will prefix the title bar of the command window with the word "Select" :

To get your program running again, you have to press escape or click somewhere else.

To get rid of this strange behavior, you can disable QuickEdit mode:

Answer 2

What I'd like to add here to Shaun Rowan's answer is that for it to work in all console windows you have to click "Defaults", instead of "Properties" and make your changes there, as described in this post.

Answer 3

I faced this problem very recently where one of the users (who had Quickedit configured on his Command Prompt) was using a tool I developed in Java, and was getting the tool frozen while running it from command prompt.

Finally what solved the problem was to redirect the logging inside the batch script to a file as shown below:

@echo off
...
java.exe -jar mytool.jar

needed to be updated to

java.exe -jar mytool.jar > log.txt

Answer 4

It's possible to disable the annoying QuickEdit Mode programmatically by importing Windows' Kernel32.dll library and using the console API functions GetStdHandle, GetConsoleMode, and SetConsoleMode through your language's native interface (e.g., Java's JNI, Python ctypes).

Python with ctypes:

Short (disables everything except EXTENDED_FLAGS). Read SetConsoleMode documentation for more detail.

import ctypes

kernel32 = ctypes.windll.kernel32
kernel32.SetConsoleMode(kernel32.GetStdHandle(-10), 0x80)

Longer (disables QUICK_EDIT_MODE without altering other settings)

import ctypes
import time
import threading

# Constants
STD_INPUT_HANDLE = -10

# Enum for ConsoleModes
class ConsoleModes(ctypes.c_uint):
    ENABLE_PROCESSED_INPUT = 0x1
    ENABLE_LINE_INPUT = 0x2
    ENABLE_ECHO_INPUT = 0x4
    ENABLE_WINDOW_INPUT = 0x8
    ENABLE_MOUSE_INPUT = 0x10
    ENABLE_INSERT_MODE = 0x20
    ENABLE_QUICK_EDIT_MODE = 0x40
    ENABLE_EXTENDED_FLAGS = 0x80
    ENABLE_AUTO_POSITION = 0x100

# Import kernel32.dll functions
kernel32 = ctypes.windll.kernel32
GetStdHandle = kernel32.GetStdHandle
GetConsoleMode = kernel32.GetConsoleMode
SetConsoleMode = kernel32.SetConsoleMode

def disable_quick_edit_mode():
    std_in = GetStdHandle(STD_INPUT_HANDLE)
    mode = ctypes.c_uint()
    if GetConsoleMode(std_in, ctypes.byref(mode)):
        if mode.value & ConsoleModes.ENABLE_QUICK_EDIT_MODE:
            mode.value ^= ConsoleModes.ENABLE_QUICK_EDIT_MODE
            SetConsoleMode(std_in, mode)

def print_numbers():
    i = 0
    while True:
        time.sleep(0.3)
        print(i)
        i += 1

def main():
    disable_quick_edit_mode()
    threading.Thread(target=print_numbers).start()

if __name__ == "__main__":
    main()

Keep in mind that this code only runs on Windows. If you are writing software to be run on multiple operating systems, make sure to safeguard against errors.

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Read More

C#:

• My UI hangs when I select some area in the console
• How to programmatic disable C# Console Application's Quick Edit mode?

Batch:

• How can I automate the process of customizing the command prompt?
• Windows BATCH: How to disable QuickEdit Mode for individual scripts?