Blog - Technical Articles

SYMPTOMS
If a Windows Service running under Local System Account, System.Security.Principal.WindowsIdentity.GetCurrent().Name.ToString() returns NT AUTHOURITY\SYSTEM

You want to get who logged on to the machine?

CAUSE
Windows Service is running under Local System Account. Current user credentials will be NT AUTHOURITY\SYSTEM. You have to query WMI to get current users logged on to the machine.

WORKAROUND
To work around this problem, use following code.

ManagementObjectSearcher searcher = new
ManagementObjectSearcher("SELECT UserName, Name FROMWin32_ComputerSystem");

foreach (ManagementObject mo in searcher.Get()) {
if (mo["UserName"] != null) {
vUserName = mo["UserName"].ToString();
}
if (mo["Name"] != null) {
strComputer = mo["Name"].ToString();
}
}
searcher.Dispose();
searcher = null;

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