CODESYS introduced many cyber security related changes over the last few years, one of them is to restrict file access. By default, file access is restricted to the PlcLogic folder and subfolders of the CODESYS control runtime of version 3.5.19.0 and newer. For Control Win this would be the folder C:\ProgramData\CODESYS\CODESYSControlWinV3x64\xxxxxxxx\PlcLogic\ To enable access to other folders, you can configure additional paths by adding them to the file CODESYSControl.cfg. For example: [SysFile]...
You may just need to create a boot application: https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_creating_a_boot_application.html