What do the folder structure and mount commands look like?

Either it was added after the directory was mounted and DOSBox hasn't refreshed the cache or it includes an invalid character

The mount command was:

mount c c:\SWOSTo~1\run\p02_sw~1

Which is where the Sensible World of Soccer .exe and the add-on program .exe are. The add-on program has an 8.3 name, all alpha, no special characters.

What do you mean when you say "missing from the dir listing" ? Do you actually mean you don't see the file when you type "dir" , or can you just not run it? (I'm wondering this because "developed under DOS on an XP machine" doesn't really make any sense.)

Also, when you look at the file's Properties in Windows Explorer, it doesn't have the Hidden attribute checked, does it?

The .exe is visible in Windows Explorer and does not have the hidden attribute checked.

To be clear, I am trying to run this program under DOSBox on a Vista machine having developed it many years ago using a DOS-based BASIC compiler. I have recently made some changes to it on an XP PC.

As I said in my first post, I am new to DOSBox on Vista and may not have understood how to configure it for this program. I already have Sensible World of Soccer working through DOSBox on the Vista PC but that is through a game launcher.

Fair enough. So what about:

Jorpho wrote:

What do you mean when you say "missing from the dir listing" ? Do you actually mean you don't see the file when you type "dir" [in DOSBox], or can you just not run it?

Does the file in question have a long file name, i.e. a name that includes a space?

I suggest you show a screenshot of explorer of that folder and one with dosbox (withe mount commands and the dir command).
What happens when you try to execute it?

The file is named SWOSCARE.EXE. Trying to execute it does nothing.

The screenshots from Explorer and DOsBox are attached.

This is very odd.

What if you try copying the entire directory to a flash drive, and then try to mount the directory on the flash drive? (Flash drives are normally FAT32-formatted, so it there's some weird NTFS security thing going on, this may help in the diagnosis.)

Why is the explorer icon for sws.exe different from swoscare.exe??

Jorpho:

You are on the right track with your suggestion. SWOSCARE is visible and runs within DOSBox when I mount it from a flash drive.

wd:

I don't know why the icons are different but I now suspect that the little blop in the right hand corner of the SWOSCARE icon may be related to the NTFS security Jorpho was talking about.

I stiil need to get it work on the C: drive because that is where the files will be but we are making progress, thank you both.

On a closer look that blob in the right hand corner is a flag for 'Run as Administrator'.

Unticking that in the file properties removes the blob but it still does not show up in DOSBox.

Delete the file from c and copy it back from the flash drive. Security stuff should then be gone.

There's certainly no "hide random files" functionality in dosbox. Check the permissions and accessibility rights,
as Jorpho says easiest way would be copying the file onto a medium that doesn't transport the access mode.

Instead of copying everything to a flash drive, I have transferred it to a folder within my user(c:\Users\me\SWOS) and all works fine.

If anyone has the patience to explain to me how I check and possibly change all the permissions and accessibility rights to make the previous set-up work, I will give it a go.

It's kind of hard to say without knowing more about your system.

If you disable "Simple File Sharing" (Google will tell you how), you can fine-tune the accessibility parameters for individual files, but I can't say why they would be different for this one file, why they would be affecting DOSBox, or how you would change them to fix the problem.

As stated by others previously, the easiest method is likely to: copy files to a location where the issue doesn't occur, delete them from the original location, and then copy them back.