Can't write to 64-bit registry using .NET C#

Question

I want to write to this registry

SOFTWARE\\Wow6432Node\\Microsoft\\Windows\\CurrentVersion\\Run

I tried this:

RegistryKey registryKey64 = RegistryKey
    .OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64)
    .OpenSubKey("SOFTWARE\\Wow6432Node\\Microsoft\\Windows\\CurrentVersion\\Run");

registryKey64.SetValue("CTIPopupForIPPhone", Application.ExecutablePath);

and I got this exception:

An unhandled exception of type 'System.UnauthorizedAccessException' occurred in mscorlib.dll

Additional information: Cannot write to the registry key.

though I am running my Visual Studio as an administrator.

Update

During the development, I also tried

RegistryKey registryKey = Registry.CurrentUser
    .OpenSubKey("SOFTWARE\\Wow6432Node\\Microsoft\\Windows\\CurrentVersion\\Run", true);

but I got error that the entry doesn't exist though it is there, but I thought that because the RegistryKey is for Windows 32-bit not 64-bit.

can you access this registry through registry editor ? And can u update it from registry editor ? — Kapoor, Oct 17 '15 at 15:40
Obviously not !! it was a check if u have the permissions to access the registry at first place ... then one can isolate if its a software issue or a permission (registry issue ) — Kapoor, Oct 17 '15 at 15:45
Possible duplicate of [cannot write to the registry key](http://stackoverflow.com/questions/7202752/cannot-write-to-the-registry-key) (or possibly [Cannot write to Registry Key, getting UnauthorizedAccessException](http://stackoverflow.com/questions/4463706/cannot-write-to-registry-key-getting-unauthorizedaccessexception)). — Ilmari Karonen, Oct 20 '15 at 14:11

score 2 · Accepted Answer · edited Oct 20 '15 at 09:56

2

This works for me,

RegistryKey registryKey64 = RegistryKey
    .OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64)
    .OpenSubKey("SOFTWARE\\Wow6432Node\\Microsoft\\Windows\\CurrentVersion\\Run", true);

The new variable true is to both read and write over registry entry to allow both of them.

edited Oct 20 '15 at 09:56

answered Oct 17 '15 at 15:48

Marco Dinatsoli

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It's worth adding a link to [MSDN](https://msdn.microsoft.com/en-us/library/xthy8s8d(v=vs.110).aspx) which explains what the additional Boolean parameter does - "If writable is true, the key will be opened for reading and writing, otherwise, the key will be opened as read-only". – Daniel Kelley Oct 20 '15 at 09:43
@DanielKelley exactly, the parameter is for write and read together it – Marco Dinatsoli Oct 20 '15 at 09:44

Can't write to 64-bit registry using .NET C#

Update

1 Answers1