is illegal in an expression for a directoryin autohotkey

Question

So im confused why this is a illegal expression its saying Z:\ is it

#SingleInstance,Force

If Exist Z:\
    Goto BackupStart
else 
Return 

BackupStart:
Msgbox,,Test,Test

Answer 1

You can use either If[Not]Exist (deprecated)

IfExist Z:\

or the FileExist function

If FileExist("Z:\")

to check for the existence of a file, folder or drive.