A quick first thought on a hack, on the development system adjust the colors for each company to be some unique and bright color.  Shown is the "normal" color.  Uncheck the Default checkbox.

Once the Default checkbox is unchecked, click the elipse button to pop the color selector.

You are then presented with choices.  Here I chose a bright yellow color.  Notice the bottom bar on the main form.  Click OK to accept the yellow color.

Notice the bottom bar now shows a portion with bright yellow.  I don't recall if I had to shut down the form first

Most forms in the system will now show this bottom toolbar color behavior.  This hack can be easily done, but does not solve your issue.  You would need to have developers specifically look for the color chosen.  Even if a real fix to address your system, this might be a good idea on a development system just to help remind developers they are on a development database.

Thank you very much.  I like this and will put in place on our test environment.

Another option is if your Sage 500 ERP business desktop is being launched from a shortcut, you can change the shortcut properties to display your icon of choice. 

Note that this type of resolution is not Sage 500 ERP related and is driven by Microsoft Windows.  If you right-click on an icon, you can often get an "Open File Location" option.  If that points to a shortcut rather than an actual executable, then this type of resolution may work.  For example, I have a Sage 500 button on  my Start Menu, and that button points to a shortcut that launches the executable, so I can change the shortcut executable.

You may be able to use an icon editor application to extract and modify existing icons.

Thank you.  We will look at this.