# Discon.dll loading **URL:** \ **Category:** Computer-Aided Engineering Software Tools\ **Created:** [July 24, 2025, 6:54am UTC](https://forums.nlr.gov/t/discon-dll-loading/9125 "2025-07-24T06:54:55Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Florian.Stache](https://avatars.discourse-cdn.com/v4/letter/f/d07c76/32.png) [@Florian.Stache](https://forums.nlr.gov/u/Florian.Stache)\ **Post date:** [July 24, 2025, 6:54am UTC](https://forums.nlr.gov/t/discon-dll-loading/9125/1 "2025-07-24T06:54:55Z")
Hi All, I´m facing issues loading the DLL with any FAST, openFAST version since a couple of days. My setup is that I start the openFAST.exe from a folder where I have all my different versions of openFAST.exe (C:\tools) and load my fst file which is in my actual project folder (i.e. C:\sim\IEA10MW\001\run). Until now I had also the DISCON.DLL stored in that run folder as this is normally project specific. Now when I run FAST I get the error: FAST\_InitializeAll:SrvD\_Init:BladedInterface\_Init:The dynamic library turbine/discon.dll could not be loaded. Check that the file exists in the specified location and that it is compiled for 64-bit applications. It was not happening before 1 or 2 weeks with the same models (I did not change anything). In order to have it running I need to move now the DISCON.DLL into the folder from where the exe is started (in my case C:\tools). My suspicion is that some windows settings have changed but I don´t know which ones. By the way it happened on all my different computers but not at the same time (probably after some windows update). Does anybody have the same issue and found a solution? (putting the DISCON.DLL in the tools folder is not an option) Principally it works when adding the full path to the DLL\_FileName parameter in the servodyn file but now I have a case where I need more flexibility and want to use relative path and there I don ´t get it and want it back to the older way where it took the DLL from the run folder where my fst file is located. Thank you for your support! ---
**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\ **Post date:** [July 24, 2025, 12:40pm UTC](https://forums.nlr.gov/t/discon-dll-loading/9125/2 "2025-07-24T12:40:38Z")
Dear @Florian.Stache, If I understand correctly, you have _OpenFAST.exe_ located in `C:\tools` and your input files (which I’ll call _Input.fst_) located in `C:\sim\IEA10MW\001\run` and you run OpenFAST from the command prompt as follows: `C:\tools>OpenFAST.exe C:\sim\IEA10MW\001\run\Input.fst` Is that correct? If so, this means that _DISCON.dll_ would have to be located in `C:\tools`, use a path relative to `C:\tools`, or use a full path to a different directory. Alternatively, you can set the `C:\tools` directory in your search path as an Windows environment variable and then you run the OpenFAST executable from any directory. E.g., from the command prompt you could use: `C:\sim\IEA10MW\001\run>OpenFAST.exe Input.fst` in which case, _DISCON.dll_ would have to be located in `C:\sim\IEA10MW\001\run`, use a path relative to `C:\sim\IEA10MW\001\run`, or use a full path to a different directory. Best regards, ---
**Author:** ![Florian.Stache](https://avatars.discourse-cdn.com/v4/letter/f/d07c76/32.png) [@Florian.Stache](https://forums.nlr.gov/u/Florian.Stache)\ **Post date:** [July 24, 2025, 1:54pm UTC](https://forums.nlr.gov/t/discon-dll-loading/9125/3 "2025-07-24T13:54:27Z")
Hi Jason, That was it! Somehow my path variables must have been changed during a windows update. I added the tools folder to the path and it is back working again. Thank you ! Best Regards, Florian