Newbie question

I have a trial version of Script Debugger 7, my old version 5 used to define alias’s as
“Macintosh HD:Users:graphics4:Desktop:PROOFS:X.pdf”
but 7 sometimes shows the alias as alias “/Users/graphics4/Desktop/PROOFS/X.pdf”

why does it use the slashes instead of colon sometimes?

What do you mean by “define aliases”? Where and how?

as in
Tell application “Finder”
set mySwapFile to “Macintosh HD:Users:graphics4:Desktop:Templates:swap.xlsx” as alias
duplicate mySwapFile to this_folder
set mySwapFile to (this_folder & “swap.xlsx” as string) as alias
open mySwapFile
end tell

Are you running Mojave, by any chance? There was an issue where AppleScript was wrongly displaying aliases like this. (It’s an issue Script Debugger has no control over — it just displays what AppleScript returns.)

Also, this line:

set mySwapFile to (this_folder & “swap.xlsx” as string) as alias

is a bit risky because the result will depend on what text item delimiters is set to. You’re creating a list and then coercing that to a string. Better to use something like:

set mySwapFile to ((this_folder as text) & “swap.xlsx”) as alias