...One would think that users should not have problems with simply downloading a file from the Internet without changing its name. However, a portion of users does every time (causing support costs and reducing Fuji's motivation to provide frequent updates), that's why Fuji is thinking about switching to an update server that takes care of the entire process.
To be fair, I have seen this type of issue frequently on other brand forums. There are two or three recurrent issues. First, there seems to be a variation in how different O/S handle downloads, particularly zip files. Windows and Apple default behaviour is not the same. Second, the usual advice is to download to desktop. I know of no-one who does this as a matter of course, preferring a dedicated "downloads" folder. And here is where the third issue lies. If you already have an existing file by that name you will either be prompted to save as a different filename or the file will be saved anyway with an extension such as (2).
It is easy to blame user error - and that is often the case - but the published process is not always foolproof even when followed assiduously thanks to the nannying interventions of O/Ss which think they know what you want better than you do...
The best solution I have found is:
1) keep a small SD card for each camera you own, dedicated to firmware updates. Format it in camera before first use.
2) When there is a new update, download it to your usual folder and drag it onto the SD card. Check that the file size corresponds to what is said on the manufacturers website.
3) Perform the update. Check that it has processed correctly, THEN DELETE THE FILE FROM YOUR COMPUTER BUT KEEP IT ON YOUR SD CARD - you thus still have it if you need it.
4) When a new firmware update is made available format your SD card in camera and start again.
I have followed this discipline for years and across multiple cameras without mishap.