Find and remove registry key in C#

Question

I'm looking for a script which can find a registry key and delete it. My key is like : "{24EAA2C1-3EE7-40E0-AEA3-D20AA14A6005}". THis key is stored in many places:

HKEY_CLASSES_ROOT\CLSID\{MY_KEY}
HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{MY_KEY}
HKEY_CURRENT_USER\Software\Classes\CLSID\{MY_KEY}
HKEY_CURRENT_USER\Software\Classes\Wow6432Node\CLSID\{MY_KEY}
HKEY_USERS\S-1-5-21-1786904987-2011555162-1551513139-1001\Software\Classes\CLSID\{MY_KEY}
HKEY_USERS\S-1-5-21-1786904987-2011555162-1551513139-1001\Software\Classes\Wow6432Node\CLSID\{KEY}
HKEY_USERS\S-1-5-21-1786904987-2011555162-1551513139-1001_Classes\CLSID\{MY_KEY}
HKEY_USERS\S-1-5-21-1786904987-2011555162-1551513139-1001_Classes\Wow6432Node\CLSID\{MY_KEY}

But these locations may vary (that's the reason why I have to find them before to delete them). I would like to remove each occurances of this key using a C# script (in a console application)

I tried this:

static void Main(string[] args)
{
    DeleteKeyTest("{MY_KEY}");
}

private RegistryKey baseRegistryKey = Registry.ClassesRoot;
public void DeleteKeyTest(string KeyName)
{
    try
    {
        RegistryKey rk = baseRegistryKey;
        rk.DeleteSubKey(KeyName);       
    }
    catch (Exception e)
    {
    }
}

I get an error:

Can not delete a subkey, because it does not exist.

EDIT

Here is my code which is used to find all the occurances of the key:

public List<string> SearchKey(string Key)
{
    List<string> ListKeys = getKeyPath(Key, RegistryKey.OpenBaseKey(RegistryHive.ClassesRoot, RegistryView.Registry64));
    ListKeys.AddRange(getKeyPath(Key, RegistryKey.OpenBaseKey(RegistryHive.CurrentUser, RegistryView.Registry64)));
    ListKeys.AddRange(getKeyPath(Key, RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64)));
    ListKeys.AddRange(getKeyPath(Key, RegistryKey.OpenBaseKey(RegistryHive.Users, RegistryView.Registry64)));
    ListKeys.AddRange(getKeyPath(Key, RegistryKey.OpenBaseKey(RegistryHive.CurrentConfig, RegistryView.Registry64)));
    return ListKeys;
}

private List<string> getKeyPath(string key, RegistryKey registryKey)
{
    List<string> keys = new List<string>();
    if (CanReadRegistryKey(registryKey))
    {
        foreach (string keyname in registryKey.GetSubKeyNames())
        {
            if (keyname.Contains(key))
                keys.Add(registryKey.Name + "\\" + keyname);

            if (CanReadKey(registryKey, keyname))
                keys.AddRange(getKeyPath(key, registryKey.OpenSubKey(keyname, RegistryKeyPermissionCheck.ReadSubTree)));
        }
    }
    return keys;
}

private bool CanReadRegistryKey(RegistryKey registryKey)
{
    try
    {
        registryKey.GetSubKeyNames();
        return true;
    }
    catch (UnauthorizedAccessException e)
    {
        return false;
    }
}

private bool CanReadKey(RegistryKey registryKey, string keyname)
{
    try
    {
        registryKey.OpenSubKey(keyname, RegistryKeyPermissionCheck.ReadSubTree);
        return true;
    }
    catch (SecurityException e)
    {
        return false;
    }
}

Usage :

List<string> ListKeys = SearchKey("MY_KEY");

I do not always get the same result. Sometimes I get 7 keys found, sometimes 8. (The missing key is HKEY_CLASSES_ROOT\Wow6432Node\CLSID{MY_KEY})

Here is my code for deleting:

public int RemoveKey(string Key)
{
    int count = RemoveKeys(Key, RegistryKey.OpenBaseKey(RegistryHive.ClassesRoot, RegistryView.Registry64));
    count += RemoveKeys(Key, RegistryKey.OpenBaseKey(RegistryHive.CurrentUser, RegistryView.Registry64));
    count += RemoveKeys(Key, RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64));
    count += RemoveKeys(Key, RegistryKey.OpenBaseKey(RegistryHive.Users, RegistryView.Registry64));
    count += RemoveKeys(Key, RegistryKey.OpenBaseKey(RegistryHive.CurrentConfig, RegistryView.Registry64));
    return count;
}

private int RemoveKeys(string key, RegistryKey registryKey)
{
    int count = 0;
    if (CanReadRegistryKey(registryKey))
    {
        foreach (string keyname in registryKey.GetSubKeyNames())
        {
            count += RemoveKeys(key, registryKey.OpenSubKey(keyname));
            try
            {
                if (keyname.Contains(key))
                {
                    registryKey.DeleteValue(keyname);
                    count++;
                }
            }
            catch (Exception e)
            {
            }
        }
    }
    return count;
}

Usage :

int NumberOfRemovedKeys = RemoveKey("MY_KEY");

But I allway got an error on this code:

registryKey.DeleteValue(keyname);

Error message :

System.UnauthorizedAccessException: Can not write to the registry key.

I got the same error when I try to launch the application in admin mode. But when I try to remove manualy the key from regedit, there is no problem.

In the "search" code, I got a list of key, with the full path. I've tried to remove the key directly using the full path but it's not possible because RegistryKey has to be initialized using RegistryHive (for exemple RegistryHive.ClassesRoot), but the RegistryHive is allready in the full path.

How can I get the authorization to remove ?

Joan Caron Joan Caron · Accepted Answer · 2013-08-30T09:55:24

You have a complete example Read, write and delete from registry with C#

And MSDN Doc

It's a good start, hope it helps!

Find and remove registry key in C#

2 Answers