Windows 20h2 Twain hangs on open

John R. Quick 6 Reputation points
2021-09-04T18:09:18.187+00:00

With Windows 10 V1909 and earlier, our Twain interfaces worked fine. With the 20h2 update the system hangs when trying to open the device. I've download other sample Twain applications such as Twack_32 and they all have the same problem.

I'm trying to access a Canon PowerShot A1100IS but know of at least a dozen other cameras from other manufactures that also stopped working with this update.

The only thing that has changed was the Windows update. We have stopped the Windows 10 20H2 updates for nearly 2000 laptops since Version 1909 is working but cannot stay on that version indefinitely.

Is there a USB security change or setting that is needed with 20H2?

This is the specific call to twain_32 that hangs

TW_UINT16 twRC = CallDSMEntry(&m_appID,
NULL,
DG_CONTROL,
DAT_IDENTITY,
MSG_OPENDS,
&m_dsID);

where CallDSMeEntry is defined as

TW_UINT16 CTwain::CallDSMEntry(pTW_IDENTITY pApp, pTW_IDENTITY pSrc,
TW_UINT32 DG, TW_UINT16 DAT, TW_UINT16 MSG, TW_MEMREF pData)
{
TW_UINT16 twRC = (*m_lpDSM_Entry)(pApp, pSrc, DG, DAT, MSG, pData);

Here is a similar code example: https://github.com/twain/twain-toolkit/blob/master/twacker/DCA_ACQ.C

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  1. John R. Quick 6 Reputation points
    2021-09-07T16:17:41.257+00:00

    The Cameras work find. You can mount them and navigate to the images but the Twain interface is not working.

    Updating to 21H1 made no difference.

    1 person found this answer helpful.
    0 comments
  2. Limitless Technology 39,351 Reputation points
    2021-09-06T15:23:50.537+00:00

    Hi there,

    Have you tired updating to 21H1 update and see if that is helpful. You can check the release information for 20H2 update here https://learn.microsoft.com/en-us/windows/whats-new/whats-new-windows-10-version-20h2,

    You have also stated that camera is not working , so it seems that their is a driver conflicts with the PC. I advice you to update all drivers from the PC manufacturer website and then try the 21H1 update.

    Hope this Answers all your queries , if not please do repost back .
    If an Answer is helpful, please click "Accept Answer" and upvote it : )

    0 comments
  3. S.Sengupta 15,111 Reputation points MVP
    2021-09-08T01:12:11.457+00:00

    Uninstall, reinstall and update your scanner driver....does it make any difference?

    0 comments
  4. John R. Quick 6 Reputation points
    2021-09-08T14:07:51.593+00:00

    Windows sees these as "MTP USB Device". Uninstalling and reinstalling makes no difference.

    I know of 17 different cameras from many different manufactures with this same problem.
    Canon, GE, Sony and Nikon.

    I don't know of any camera that works with Twain after the 20h2 update

    0 comments
  5. Robert Hanan 1 Reputation point
    2021-11-18T19:48:13.373+00:00

    We have experienced this same issue: upgrade to 20H2; multiple brands & models of digital cameras now fail to connect, and the software fails to transfer images as the TWAIN interface hangs.

    @John R. Quick , have you managed to resolve this issue?