Creating new value inside registry Run key with Python?

Question

I am trying to create a new value under the Run key in Windows 7. I am using Python 3.5 and I am having trouble writing to the key. My current code is creating a new key under the key I am trying to modify the values of.

from winreg import *

aKey = OpenKey(HKEY_CURRENT_USER, "Software\Microsoft\Windows\CurrentVersion\Run", 0, KEY_ALL_ACCESS)

SetValue(aKey, 'NameOfNewValue', REG_SZ, '%windir%\system32\calc.exe')

When I run this, it makes a key under the Run and names it "NameOfNewKey" and then sets the default value to the calc.exe path. However, I want to add a new value to the Run key so that when I startup, calc.exe will run.

EDIT: I found the answer. It should be the SetValueEx function instead of SetValue.

Grison

Have you tried manually adding it first, making sure it works? Then trying to convert that into code? – Digestion

This above is not working as intended. Even if I add a value under the Run key it will just make a new key under the Run key instead of making a value under the Run key. Edit - Found the answer, put in OP. – Grison

can you put your full code snippet in just to make sure anyone who comes here in future has a working code sample to look at? Thanks – Digestion

Answer 1

Here is a function which can set/delete a run key.

Code:

def set_run_key(key, value):
    """
    Set/Remove Run Key in windows registry.

    :param key: Run Key Name
    :param value: Program to Run
    :return: None
    """
    # This is for the system run variable
    reg_key = winreg.OpenKey(
        winreg.HKEY_CURRENT_USER,
        r'Software\Microsoft\Windows\CurrentVersion\Run',
        0, winreg.KEY_SET_VALUE)

    with reg_key:
        if value is None:
            winreg.DeleteValue(reg_key, key)
        else:
            if '%' in value:
                var_type = winreg.REG_EXPAND_SZ
            else:
                var_type = winreg.REG_SZ
            winreg.SetValueEx(reg_key, key, 0, var_type, value)

To set:

set_run_key('NameOfNewValue', '%windir%\system32\calc.exe')

To remove:

set_run_key('NameOfNewValue', None)

To import win32 libs:

try:
    import _winreg as winreg
except ImportError:
    # this has been renamed in python 3
    import winreg

Thulium

Works perfectly for me. – Chukchi

Answer 2

I ran into this same problem. The source of confusion here is the poorly named functions:

• winreg.SetValue(): sets or creates a subkey
• winreg.SetValueEx(): sets or creates a named value

Normally when a function has an "Ex" suffix, it means the caller can specify additional arguments for the same operation. In this case, the functions have different semantics; the "SetValue()" should have been named something like "SetKey()".

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