Firstly, I am a naive developer and have no much indepth understanding of these codes. I am getting access denied in the code block which tries to get the version number of one of the application.
Scenario : There is no issue while running the code in a visual studio. But when the installation file is ran in different machines and log is inspected, it throws an Win32Exception: Access is denied.
(Program runs automatically right after installation. Actually before installing this application there would already be a watchdog service installed which automatically runs the application and revives it on closing. So, I believe I cannot set requestedExecutionLevel to requireAdmin which might display confirm dialog and give user the control over running the application.)
I am required to address this problem. After reading some blogs I believe this must be due to the lack of enough rights to retrieve the required information. But I am still unclear about how to address/solve this.
Exception from log file :
[  1,11216] 2017-04-17T11:43:53 - -------------------- Win32Exception caught --------------------
[  1,11216] 2017-04-17T11:43:53 - Access is denied
[  1,11216] 2017-04-17T11:43:53 - (Win32Err=0x00000005)
[  1,11216] 2017-04-17T11:43:53 - Stack trace is : 
[  1,11216] 2017-04-17T11:43:53 -    at System.Diagnostics.ProcessManager.OpenProcess(Int32 processId, Int32 access, Boolean throwIfExited)
   at System.Diagnostics.NtProcessManager.GetModuleInfos(Int32 processId, Boolean firstModuleOnly)
   at System.Diagnostics.NtProcessManager.GetFirstModuleInfo(Int32 processId)
   at System.Diagnostics.Process.get_MainModule()
   at IMPMDesktopClient.BaseIMClientDriver.GetVersion(UIntPtr windowUIntPtr)
   at IMPMDesktopClient.WindowDetector.Hooks.WindowsEventArgs..ctor(Int32 eventNum, UIntPtr windowHandle, Int32 idObject, Int32 idChild, String clsName, Rectangle pos)
   at IMPMDesktopClient.WindowDetector.Hooks.EventHooks.CheckForWindowOfInterest(UIntPtr hWnd, UIntPtr arg)
   at IMPMDesktopClient.WindowDetector.Hooks.EventHooks.CheckTopWindow(UIntPtr hWnd, UIntPtr arg)
   at IMPMDesktopClient.Win32Interop.EnumWindows(WndEnumCallback callback, UIntPtr param)
   at IMPMDesktopClient.WindowDetector.Hooks.EventHooks.DetectTheseWindowsNow(List`1 classes)
   at IMPMDesktopClient.WindowDetector.WindowClassManager.OnPostRegistration()
[  1,11216] 2017-04-17T11:43:53 - --------------------Win32Exception--------------------
Code for GetVersion() :
public static Version GetVersion(UIntPtr windowUIntPtr)
    {
        var noOfTrials = 2;
        var threadSleepPeriod = 1000;
        Process imProc = null;
        while (noOfTrials > 0)
        {
            try
            {
                imProc = Win32Interop.GetWindowProcess(windowUIntPtr);
                Version version;
                try
                {
                    version = GetModuleVersion(imProc.MainModule); 
                }
                catch (System.ComponentModel.Win32Exception)
                {
                    version = GetModuleVersion(imProc.Id);
                }
                // If getting version fails, retry it.
                if (version == null || (version.Major == 0 && version.Minor == 0))
                {
                    // The thread will sleep for 1s after 1st trial, 3s after 2nd trial.
                    Thread.Sleep(threadSleepPeriod);
                    noOfTrials--;
                    threadSleepPeriod += 2000;
                }
                else
                    return version;
                if (noOfTrials == 0)
                {
                    Log.Write(...);
                }
            }
            catch (Exception ex)
            {
                Log.Write(...);
            }
        }
        return new Version();
    }
 
     
    