Bad protocol error on

Questions, comments and suggestions concerning VintaSoft Twain .NET SDK.

Moderator: Alex

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Joined: Thu May 02, 2013 9:22 pm

Bad protocol error on

Post by ricrempel » Thu May 02, 2013 9:40 pm

When I call, I get a Twain Error: "General failure in response to DAT_CAPS. Bad protocol error."

This happens in my own code, but also in the demos provided by VintaSoft. The error is shown in a message box, displayed by the scanner software.

My scanner is a VistaScan, used to scan dental radiographies, so not a very common equipment.

After I close the message, scanning proceeds and I can acquire the images.

My setup: Windows 8 64bits, VintaSoftTwain.NET SDK 8.3 (x86), scanner uses Twain 1.9. Same problem happens on a Windows 7 machine. I have tried changing various parameters, to no avail.

I'm about to purchase Vintasoft's solution, but cannot until this problem is solved. Please, can someone help me?


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Re: Bad protocol error on

Post by Alex » Fri May 03, 2013 9:16 am


Please generate log-file and send it to our support team at for analyze.

Here are steps which you should do if you want to generate an extended log-file of scanner's work:
1. Enable logging (add the lines below to code of your application):
TwainEnvironment.DebugLevel = DebugLevel.Debug
2. Run your application.
3. Send us a log-file and detailed description of the problem.

Best regards, Alexander

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