Nobuhiko Matsui 

So, you have received a project from someone else that was created in an older version of Trados Studio still using the old SRT filetype?  That is most likely the source of your problem.

"Subtitles v 1.0.0.0" can handle SRT files as well as many others, but since you didn't create the SDLXLIFF as part of the project creation you won't be able to save the target.  All you can do here is send the completed sdlxliff file back to your customer, and they will be able to save the target.

Nobuhiko Matsui 

So, you have received a project from someone else that was created in an older version of Trados Studio still using the old SRT filetype?  That is most likely the source of your problem.

"Subtitles v 1.0.0.0" can handle SRT files as well as many others, but since you didn't create the SDLXLIFF as part of the project creation you won't be able to save the target.  All you can do here is send the completed sdlxliff file back to your customer, and they will be able to save the target.

Paul,

Thank you very much for your reply.

I now understand that there’s no backward compatibility for file types in this case.

I ended up doing exactly what you suggested—I sent the translated .sdlxliff files back to my customer for them to generate the final version of files for my check/review. I’ve also asked them to avoid creating future projects with the old SubRip file type.

Thank you again for your helpful comment.