Hi, I imported the libft4222.dll to created library but encountered dll load failed when I tried to use them.it complains ordinal 90 not found in fd2xxx.dll then it complains libft4222.dll load failed since operating system not run in %1.any help would be appreciated.My labview is 2014. 32bits.

Usually the ftd2xx.dll file gets installed into the Windows system directory. Check there (System32 on 32 Bit Windows and SysWOW64 on 64 Bit Windows for 32 Bit applications). The other DLL might try to load the file from there but gets a problem if you already load that DLL in LabVIEW from a different place. If you find the ftd2xx.dll in the system directory, change the Call Library Nodes for that DLL to only contain the DLL file name without Windows system directory path. That will avoid problems when you or someone else later tries to build an executable containing these VIs. Yes that means that any user of your LabVIEW application will actually need to install the FTDI driver on his system, but that is clearly how FTDI has designed this and therefore you should follow that. If this doesn't help you really need to open a support ticket with FTDI. They are the only people who know how they build their DLLs and how they are supposed to work together. LabVIEW isn't doing anything special with DLLs that would cause this problem (but you are doing that by explictly pointing the LabVIEW VIs to the ftd2xx.dll path). Your sample programs only link with the import library ftd2xx.lib and that does not reference the DLL by full path but only the library name alone without any path, which means that the DLLs only can be either in the same directory as the executable itself or in the Windows or System directory).