A while back, I had a user call in and tell me that he was editing a document in SPSS, and went to save his progress to the original file, when he got the following error:
The SAVE command has succeeded. However, due to contention for the specified file, the data have been saved to a file with a different name. Saved to: location\filename.sav
He further reported that the file specified was the one he was working on, and the file size had been reduced to 0kB. Looking into it, I found that this is a challenge for SPSS users for years, and is most likely caused by SPSS locking the original file, and in turn being unable to save to the same file. Knowing this, a workaround presents itself: save your work as a new file, then close and rename. Cumbersome? Sure. It will, however, prevent you from losing data.