On the mac it places a hyphen as well and saves it just fine.

The reason it puts the hyphen is because it is saved for the web and a space on the web won't work.

Like Wade says, it is not good practice to use spaces in file names for the web.

In fact one should avoid spaces in all file (and folder) names. They can amongst other things lead to confusion between mismatched operating systems.

I have even seen a space in a folder name render the enclosed Illustrator file unreadable.

Not sure why it was but it had something to do with the addressing of linked image files. As soon as we altered the folder name and adjusted the links, everything returned to normal.

Have it as you will and get into trouble if you want to. You have been warned :-)

That Adobe evidently is attempting to enforce something about best practices doesn't bother me a bit.

I don't think Adobe is trying to enforce anything. It's just that spaces in file and folder names CAN cause trouble. It doesn't always happen and you may get away with using them, but by doing so you appear to be running a certain risk.

I have been in the business for more years than I care to remember and have seen errors that could be traced to spaces maybe a couple of times since OS X.

More common are file name errors caused by obscure glyphs. ð, þ, æ, ö and accented characters, especially ý, are the most common culprits in my neck of the woods.

I just tried saving a filed called "ýþæöð asdfgh.png". Illie doesn't do anything other than I asked her to do.

However I doubt that such a file would be useable on a web page.

I also discovered recently that files with an asterix (*) in their names are not accepted by some servers.

The files can be inserted as images but somehow don't show up.

I think that may have been "best practices" in the ancient days of computing, but as the OP said, we're now well into the second decade of the Twenty-first Century and computers can handle spaces.  I'm not sure, but I think IIS has been handling spaces in filenames for a long time.

The best thing to do is test it with the Web server you're using.

If Adobe products can't handle linked files with paths having spaces in them, then it's high time Adobe fixes that, and it should be reported as a bug.  (All it takes is changing the code to add double-quotes around the fully-qualified path.)

I still hate SFW changing my file naming convention to suit itself.

Ken

Well, Adobe forces one to use "Save For Web" in order to acces a whole lot of options, such as specific file formats, sizes, etc., all of which are useful even if the final resting place of the image is not on the Web.  SFW is the only place to do that.

I'm not even sure what Ai's "Export" uses for PNG.  Is it PNG-8 or PNG-24?

Are you saying that if Adobe simply duplicated everything in SFW and included the feature by naming it "Save With Options", that's the only way they should allow saving a filename with spaces?

And how does Photoshop CS6 handle this?  Does its SFW automatically remove spaces in the filename?

Added:

I just re-read your post -- are you saying that Fireworks SFW keeps the spaces in the filenames?  Or does Fireworks simply use the SFW interface but merely re-labels the function something like "Save Optimized"?

Ken

Depends on the web server as to why spaces in filenames may or may not work. Though this works on more servers nowadays, would urge you not to run that risk or use colons or backslashes in filenames. When Mac OSX first came out the popular  "• filenames" made bullet named files invisible, or if you logged back in OS9.

Here are 2 contemporary examples where having spaces or special characters in a filename results in an error:

- images or links used in Constant Contact emails, where the image or link is tracked

- images used in the MODX Content Management System

In both these cases, it's a bit of an oversight on behalf of the developer, but regardless, the problem only shows up when the filenames fall outside these (older) best practices.