UBE: Retrieve of UBE file failed. The file may not exist on Enterprise Server.

This message started appearing a couple of days ago but only for a specific version of a UBE, and it's not constant or for all users. It will happen for hours and then be fine again. What is the most likely cause for this?

Did you try logging onto windows (fat) client and submitting version specs?

Since 8.98.4.6 (I think), if a UBE generates no data into the PDF, the blank pdf is not saved so there is no file to retrieve. Check the jde.log for the job, it should indicate no PDF saved. When there is no PDF, that is the message you get.