Getting exception while attempting to delete the COM dll file after unloading an AppDomain

Question

Getting exception while attempting to delete the COM dll file after unloading an AppDomain. Exception detail: Failed to apply auto update System.UnauthorizedAccessException: Access to the path 'IQVdxp32.dll' is denied. Code:

private bool ApplyUpdate(string tempfolderpath)
    {
        bool result;
        try
        {
            Destroy();
            if (Directory.Exists(moduledir))
                Directory.Delete(moduledir, true); /*Getting excpetion while deleting that unload appdomain directory*/
            DirectoryUtils.Copy(tempfolderpath, moduledir);
            Create();
            log.Info("Auto update successful for module : " + modulename);
            result = true;
        }
        catch (Exception exception)
        {
            log.Error("Failed to apply auto update", exception);
            result = false;
        }
        return result;
    }
 public void Destroy()
    {
        if (appdomain != null)
        {
            lock (objappdomainlocker)
            {
                if (appdomain != null)
                {
                    CoFreeUnusedLibrariesEx(10000, (UInt32)0);
                    System.Threading.Thread.Sleep((int)10000);
                    if (loader != null && apolomain != null)
                    {
                        loader.CallInternalOnObject("Destroy", null, apolomain);
                    }
                    // unload the AppDomain completely
                    AppDomain.Unload(appdomain);
                    appdomain = null;
                    loader = null;
                    apolomain = null;
                    IsPersist = false;
                 }
            }
        }
    }

[DllImport("ole32.dll")]
    public static extern void CoFreeUnusedLibrariesEx(UInt32 unloadDelay, UInt32 reserved);