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Vista 64bits/ Visual Studio 2008 and + compatibility

Mar 9, 2010 at 9:05 PM



I've just downloaded openTwain, and tried to compile with VS2008 under Vista 64 Business edition, VS2008 converted it and compiled it without any error.

I have a fully functional scanner driver running on this system (provided by Kodak). But it looks like openTWAIN is unable to find any data sources (both CLI and GUI).

I tried my own application, 32 bits, coded with VS2008 C++ unmanaged, and I'm able to scan flawlessly.

What could be wrong with openTwain, or what do I need to change inside the code or the project to make it work under VS2008 on 64bots system (and probably with VS2010 as well) ?




Mar 11, 2010 at 2:39 PM

If you compile opentwain with visual studio on an XP/2003 32bit machine does it then find your datasources?

As to what could be wrong,.. several things come to mind but I would only be throwing darts if posted my guesses.  I'm going to be updating to Win7 64 this year with vs2008 and I can test this then.

Best Regards,


Mar 11, 2010 at 7:12 PM
Edited Mar 11, 2010 at 7:14 PM

I took the binaries generated on my computer (VS2008/Vista 64bits) and tried on an XP (32 bits) computer, the software found the TWAIN drivers.

So the problem seems to be related with 64 bits OS.


Mar 17, 2010 at 10:19 PM

I replied to this eariler and my mobile phone ate the message, sorry I havent come back to re-post my reply.


Where is your twain_32.dll on your 64bit machine?

If you have native c++ code, why use opentwain?  don't get me wrong - you're more than welcome and if it can help then by all means, but what is the goal if you already have working native code?

and as I said, when I move to an 64bit Windows 7 I'll test and update the code.  might even have time to the twain 2 spec.


If you step through the code on your 64 bit machine and find the bug feel free to point it out to me,

Best Regards,

Mar 18, 2010 at 3:17 AM

I have a twain_32.dll in C:\Windows\SysWOW64.


The main reason for my interest in openTWAIN is because I need an alternate solution, managed, and easy to give to a beginner (without a deep knowledge of TWAIN). My C++ code is huge and many of my programmers have a lot of difficulties to understand this code (I'm talking of more than 75 000 lines of C++, and the full support of all capabilities (custom included) on almost any high speed production scanner (main brands), built around a million of lines of code program handling image treatment).

If openTWAIN works fine, maybe I will try to make it work in C# so I can link it with Paint.Net to have a nice standalone image treatment solution. Of course I don't expect openTWAIN to be as fast or as exhaustive as my C++ code, but a basic support will be perfect for my needs.

Unfortunately I haven't find any time yet to help you ... but at least I compiled it and make it run ... ;)

Also I'm not really a VB.Net expert too.


Jul 23, 2012 at 10:53 PM


I've the same problem, the opentwain doesn't find any datasource on W7 64 bit.

The same code run perfectly on W7 32 bit.

Could you please tell me how to run opentwain on 64 bit system?

I have a twain_32.dll under C:\Windows

Many thanks.

Sep 3, 2012 at 4:27 AM

I believe most scanner suppliers only supply 32 bit driver versions. 

Your code will not work unless your scanner is running on a 64 bit driver.