FORUM Forums Software CLS2SIM Software Windows security – Memory integrity can't be enabled caused by Brunner CLS2Sim

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    There is a security issue in Windows which seems being caused by CLS2Sim/a driver used by CLS2Sim.

    It started with me seeing a yellow exclamation mark in Windows Security. Going to the security page in Windows, I was told memory integrity was switched off. When trying to enable it, I got an error message telling me it was not possible due to incompatible drivers. Looking at the details what drivers were causing the issue, I found a driver called ftdibus.sys. I then performed a search for this driver and found how it’s part of the CLS2Sim installation.

    Attached are a couple of screenshots showing what I’m referring to above. I will create a support ticket for this as well since it’s seems like a rather serious issue to me when CLS2Sim is hindering Windows Security to be fully enabled.

    Diego Bürgin

    Hello everyone

    ftdibus.sys is an old driver that is installed by CLS2Sim, for compatibility with older devices.
    If your Brunner device has no COM port, you don’t need this driver and can uninstall it.
    However please be aware that each update of CLS2Sim will reinstall the driver.

    We are aware and working on this problem.



    Thanks for confirming the issue Diego!

    Without unscrewing my CLS-E from the desk, allowing me to look at the rear of it, can you let me know if I could uninstall the ftdibus.sys driver? Based on what you say about older devices, I guess mine belongs to that group 🙂

    Also, in the event I could uninstall the driver while you’re working on a permanent fix for tis issue, how do you uninstall the driver?


    Was notified about CLS2Sim but when I try to download it by following the link, I get an error message telling me ‘403 Forbidden’ and how I don’t have permission to download the file. Even when I’m logged on as ‘Software’.

    Can’t recall seeing this one before.


    Just try again


    Worked fine now, thanks.

    Still seem to have the same issue with ftdibus.sys after updating to this newest version but guess it was not yet addressed in this version of CLS2Sim?

    I’m also waiting for an answer how to uninstall the driver if/when it’s not needed.


    Just tried 5.1.21 and using this version of CLS2Sim, my CLS-E fails to connect. Going back to 5.1.18, it connects just fine.


    I have the same problem with my old (first) CLS-E Yoke (this with COM-Port) and 5.1.21. The Yoke fails to connect. 5.1.18 works without problems.


    Here too. I’m opening a ticket.


    Same here, unable to use my CLS-E. Unfortunately deleted 5.1.18.

    Diego Bürgin

    Hello everyone

    a) CLS2Sim not connecting:
    We have just now uploaded CLS2Sim build 5.1.23 which fixes the particular problem.

    b) Memory integrity:
    CLS2Sim ships and installs an old FTDI driver (older version for compatibility reasons).
    The offending driver installer has been removed.

    For user with old hardware using a COM-Port:
    IF you have Windows 8+, it will automatically install a new version of the driver when the device is plugged in.
    If you Windows 7 or older and connections problems, contact us.

    People with the memory integrity issue will need to uninstall the old driver manually:
    Uninstall the following 2 items from “Control Panel” > “Programs and features”

    Windows Driver Package – FTDI CDM Driver Package – VCP Driver (01/27/2014 2.10.00) – 01/27/2014 2.10.00
    Windows Driver Package – FTDI CDM Driver Package – Bus/D2XX Driver (01/27/2014 2.10.00) – 01/27/2014 2.10.00



    Brilliant Diego, many thanks for addressing the issues so quickly and I can confirm both issues fixed over here updating to the latest version of CLS2Sim and following your advice on removing the old driver packages.

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