DotTwain has tracing code added to it in order to help us debug a problem. You can enable tracing by adding an Application Configuration File (app.config) to your project. Then add the following code to create a TraceSwitch named "Atalasoft.Twain".
<add name="Atalasoft.Twain" value="4" />
<trace autoflush="true" indentsize="4">
<add name="DotTwainListener" type="System.Diagnostics.TextWriterTraceListener" initializeData="c:\users\YOUR_USERNAME\Documents\DotTwain.log" />
When you run your project, the DotTwain trace information will be listed in the Output - Debug window within Visual Studio. The above code also creates a listener that will output the trace information to a log file (c:\users\YOUR_USERNAME\Documents\DotTwain.log).
IMPORTANT: set the InitializeData path to a location that the user running the app has full write access to and make sure the folder exists. This article used to say c:\DotTwain.log but we found that direct writing to the root of the C drive failed for non administrative users.
Please consider creating a directory under your profile then providing the full path to that such as
If no log is written, try running the application as administrator... and make sure the path defined exists and is writable
You can learn more about tracing from MSDN: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon/html/vbconconfigurationoftraceswitches.asp