This KB covers the most common causes for WingScan appearing to scan, but no images are sent to the server.

This assumes you have gotten WingScan to the point where it populates your scanner list and when you start the scan your scanner appears to be scanning properly.

Potential Issue 1:

Typically the first thing I would check is that in your scanningOptions specified in your Atalasoft.Controls.Capture.WebScanning.initialize call that you have applyVRS set to false if you do not have a VRS license. If you have not, or you have set it to true but do not have a VRS license with WingScan it may seem as though everything is scanning but nothing is sent to the server. However, it does pass an explicit error in the onScanCompleted event. You can catch/log this exception with something similar to this:

Atalasoft.Controls.Capture.WebScanning.initialize({
 handlerUrl: 'ScanningHandler.ashx', /* make sure to change this to your handler */
 onScanCompleted: function (eventName, eventObj) { 
  if(!eventObj.success)
    console.log("Scanning did not complete successfully.", eventObj.error.message); 
 },
 /* Other events like onUploadCompleted, scanningOptions/etc. */
}

Potential Issue 2:

The other issue that has arisen is that this same behavior may be exhibited if your button is causing a post back on click.

Make sure the button/element you are using to start you scan doesn't have any JavaScript errors. Make sure you're not using any server-side events (for an asp:Button this means using onClickClick instead of onClick.) Make sure you're cancelling the event or returning false in the click event.

Any post backs should be obvious as the entire page will reload and you will see both the elements redraw (blank out and return) as well as any network traffic.

Original Article:
Q10377 - FAQ: WingScan appears to scan but no images are sent to the server