Indesign scripts are not working in the 2025 Indesign version.

Once upon a time script compatibility across versions was a high priority.

While AppleScript still supports the alias type for HFS paths, someone missed that InDesign's general switch to posix paths trickled thru to the scripting subsystem. And, incompletely at that.

E.g. the file path property of your active document still yields an alias.

On the other hand, the export now requires a posix file.

Btw no need for the double tell application ….

tell application id "com.adobe.InDesign"

set mgFolderAlias to file path of active document

set mgFolder to POSIX path of mgFolderAlias

set mgName to name of active document

set text item delimiters of AppleScript to {"."}

set mgShortName to text item 1 of mgName

set text item delimiters of AppleScript to ""

set page range of PDF export preferences to "All"

set mgFilePath to mgFolder & mgShortName & ".pdf" as string

tell active document

export format PDF type to mgFilePath using "Kosmos_BoardGame_2017" with page range without showing options

end tell

display alert "A pdf elkészült a Kosmos_BoardGame_2017 presettel."

end tell

Have you tried creating subfolders inside your Scripts folder for older scripts? I've got some VERY old scripts from InDesign CS2 in a 'Version 4.0 Scripts' subfolder that still work. I assume CC2024 scripts would be 'Version 19.0 Scripts'.