On new machines Leadtools is not recognizing scanner software - Had to run Twack_32 before Leadtools recognized attached scanner

I am updating our old scanning programs to v19 from v17 and installing these Clickonce apps to new 64bit windows 7 machines.
The application is still 32 bit using Leadtools 32 bit dlls.
I made changes to the code based on what I found in your version change documentation.
Though a number of other third party scanning application (e.g. Adobe pro) had no problem seeing our old Canon 9050c scanners running twain 1.9 the Leadtool methods did not work until after I ran twack_32 on the machine.

The line below was my Startup method.
twainSession.Startup(this, "LEAD Technologies, Inc.", "LEAD Test Applications", "Version 1.0", "TWAIN Test Application", TwainStartupFlags.None);

After that the Leadtools tools did detect the scanners without issue.
Can you explain why the Leadtools methods would not detect the canon drivers without running Twack_32?

Also, are there any particular known issues with updating from version 17 through to 19 that aren't from the current documentation

Could you clarify the steps you're performing to get your twain device to recognize with LEADTOOLS?

Are you unable to locate the hardware device with our SDK until after you run the Twacker utility? Or can you recognize the device only after you run the line of code that you posted?

Additionally, have you ensured that the drivers are the latest version for your particular hardware device? You can test to see if our demos can see your hardware device. Please navigate to the path provided below and run the demo to see if it recognizes your Twain hardware device.

C:\LEADTOOLS 19\Examples\DotNet\CS\TwainDemo

Let us know your results and we'll assist you from there.

Unfortunately, at this point, I can't go back in time to before I ran twacker_32 on the new machines.
The exact code from the software that failed before running Twacker_32 is copied below.
The code below would simply hang when it called twainSession.Startup().
This code now runs just fine without a line of code changed and recognizes all twain drivers on the machine.

twainSession = new TwainSession();
try
{
//TwainSourceInformation[] srcInfo = twainSession.QuerySourceInformation();
//string sourceName = twainSession.SelectedSourceName();
if (MessageBox.Show(this, "Do you have a scanner connected.", "Scanner", MessageBoxButtons.YesNo, MessageBoxIcon.Question) ==
DialogResult.Yes)
{
twainSession.Startup(Handle, "LEAD Technologies, Inc.", "LEAD Test Applications", "Version 1.0", "TWAIN Test Application", TwainStartupFlags.None);
if (twainSession.SelectSource(string.Empty) != DialogResult.OK)
MessageBox.Show("Error Selecting Source");
//if (_twainSession.)
// _twainSession.SelectSource(string.Empty);
twainSession.AcquirePage += _twainSession_AcquirePage;
//_twainSession.EnableDuplexScanning = false;
//TwainCapability twainCap = twainSession.GetCapability(TwainCapabilityType.AutoFeed, TwainGetCapabilityMode.GetCurrent);
//string twainValue = twainCap.OneValueCapability.Value.ToString();
isScannerConnected = true;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}

I have performed testing on my end by running through the code that was provided. From these tests, I was unable to reproduce the same results that you were receiving. From this, it seems that this issue may originate from the Twain drivers themselves. I would recommend downloading the latest drivers if you have not done so.

If this issue persists or comes up again, feel free to contact us again and we'll assist you from there.