Just a bit of Movable Type administrivia, which I’m posting in case anyone else has this problem: ever since I upgraded to the latest version of MT several months ago, I’ve noticed a bug in which MT will sometimes unnecessarily append “_1” to an entry’s basename when I save changes, and given the way my file publishing is set up (using truncated entry titles for filenames), that ends up creating an unwanted additional file. MT usually tacks on these extra numbers to prevent possible overwriting of otherwise identically titled entries, but it has done so even in cases where a conflicting entry doesn’t exist.
After doing a lot of Googling, I finally found an official reference to the problem. Apparently it has to do with the preview function, which I use a lot. The workaround is to avoid saving from the preview screen; instead, click on “re-edit this entry” to return to the editing screen and then save from there. (Six Apart’s explanation can be found in a comment on NSLog; scroll down to the third comment.)