Hm, I don't have any problem to start Excel from with UltraEdit.
First to launch an application independent which program is currently running is best done by creating a shortcut on your Windows desktop or in your Windows start menu and specify a hotkey in the properties of the shortcut.I have never understood why there are keyboards with special keys and drivers to start the email program or the Internet browser when I can start my email program with Ctrl+Alt+M (or AltGr+M), my Opera with AltGr+O, my IE6 with AltGr+I, my Total Commander with AltGr+T, my UltraEdit with AltGr+U, my UEStudio with AltGr+D, my IrfanView with AltGr+V, my WinRar with AltGr+R, etc.
But if you really want to start Excel with the current CSV file from within UltraEdit, that is no problem with the correct tool options.
I have tested it with following tool settings with UE v12.20b. These settings are needed for all Windows GUI applications!
Menu Item Name: Start Excel
Command Line: C:\Program Files\Microsoft Office\Office11\Excel.exe "%f"
Working Directory: %p
Toolbar bitmap/icon (file path): C:\Program Files\Microsoft Office\Office11\Excel.bmp
Program Type: Windows program
Save Active File: checked
Save all files first: not checked
Command Output (DOS Commands): Append to Existing
Show DOS Box: not checked
Capture Output: not checked
Replace selected text with: No Replace
selectedAttention: Never use double quotes around %p in the working directory field even when the current file path can contain a space. But always use double quotes around %f at the command line.
Double quotes around the full file name of the EXE and the bitmap/icon are optional. See help for the Tool configuration dialog for a detailed description of available and case-sensitive % parameters and what is the difference between %F and "%f".
I used IrfanView
to extract the 16x16 icon from Excel.exe (I use small toolbar icons) and modified with a graphic program slightly the color of pixel 0 in top left corner (red value +1) and saved it with 16 colors (4 colors counted). See my post at Colourless Icons
for an explanation for the reason of the modification of pixel 0 of the Excel icon.