Access to the registry key '[KEY_NAME]' is denied

vb.net registry unauthorizedaccessexcepti
Vinayak picture Vinayak · Oct 23, 2012 · Viewed 16.1k times · Source

I'm writing a small program in Visual Basic 2008 that flips the values of specific DWORDs in a registry key

The registry key in question is:

'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\MMDevices\Audio\Render\{91801674-82d9-459a-9358-6e5cf3d81d21}\FxProperties'

The dword I'm manipulating is "{e0a941a0-88a2-4df5-8d6b-dd20bb06e8fb},4"

This is the line of code I wrote to set the DWORD's value is this:

Dim keyString = "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\MMDevices\Audio\Render\{91801674-82d9-459a-9358-6e5cf3d81d21}\FxProperties"
My.Computer.Registry.SetValue(keyString, "{ad75efc0-8f48-4285-bfa8-40fb036cdab2},2", "00000000")

But I get a UnauthorizedAccessException at runtime stating that "Access to the registry key [KEY_NAME] is denied."

I ran the program with Administrator privileges, changed the app's manifest to include:

<requestedExecutionLevel level="highestAvailable" uiAccess="false" />

But that didn't work either. So I searched a few forums and tried this:

Dim rkLM As RegistryKey = Registry.LocalMachine
Dim pRegKey As RegistryKey = rkLM.OpenSubKey("\SOFTWARE\Microsoft\Windows\CurrentVersion\MMDevices\Audio\Render\{91801674-82d9-459a-9358-6e5cf3d81d21}\FxProperties", True)
pRegKey.SetValue("{ad75efc0-8f48-4285-bfa8-40fb036cdab2},2", "00000000")

But that threw a NullReferenceException at me stating "Object reference not set to an instance of an object."

Is there any way I can modify that that key without having to run my program with SYSTEM privileges?

Answer

Matt Wilko picture Matt Wilko · Oct 23, 2012

You should probably try with requireAdministrator in your manifest because highestAvailable may not actually be an administrator.

I would also try specifying the data type (in your case I think it is binary):

My.Computer.Registry.SetValue(keyString, _
"{ad75efc0-8f48-4285-bfa8-40fb036cdab2},2", _ 
"00000000", _
RegistryValueKind.Binary)

However the value you are setting may need to be a byte array (something else you could try)

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