Can no longer open a htm file into a browser window

Good morning, 

This issue has arrived since the last upgrade (I think), there was also Windows patching.

I would like to check if anyone else has the issue, and if there is a workaround?

The functions purpose is to open a browser, and then open a given file.

The open browser command works but it cannot find the file.

I can open the file manually into the browser just find - so it is there :), path name is good, same character case as being called.

I have tried Edge, Chrome and Firefox and have the same outcome.
File permissions have not changed

Here is the code:

var destinationAddress = "C:/Testing/" + formatStr + "_TC" + testCompleteVersionNumber + "_results.htm/index.htm";

function OpenBrowser(browserType, destinationAddress)
{
//Close browser if there is already one open
if (Sys.WaitBrowser(browserType).Exists)
{
Sys.WaitBrowser(browserType).Close();
}
Browsers.Item(browserType).Run(destinationAddress);
Sys.Browser(browserType).BrowserWindow(0).Maximize();
}

Heres the error when another file failed when trying to open

Last week I upgraded TC to 15.56.2.7 x64

Thanks Julie