Hi Shane The str2ascii.exe is part of the FEKO 2018 installation. See the bin folder of FEKO.   See the UserManual.pdf in the help folder also for further details. Attached an image for your convenience. FEKO can read back in the *.str files but not *.os files.     Run a model with export to *.str file set (Save/Read currents in Solver settings) Run "str2ascii <filename.str> -r > ascii.str" and get a file "ascii.str" with an ASCII forma