I have an assembly file created in SW 2019. I have to give it to a vendor which only has SW 2017. They asked me to save Step files. I have saved the assembly as a Part file first, then tried to save it as either of the Step file types. Both make the system think for a while, then save the file as a 1kb .ERR file. I also tried saving the files as both parasolid file types. The computer thought about it for a while, then......nothing. No error message, no sign of a file in the folder. 

How do I get this assembly into a Step file?