Had that for other marketplace purchases in the past.
Can you try to locate your OneStore folder (next to Community), delete the junkers folder, and download again from inside the sim (need to relaunch sim first).
On top of deleting the junkers folder in OneStore folder, you also need to delete any .fspatch (or similar, can’t remember the exact name) file that is in the OneStore folder. Those are pending updates that might have been corrupted.
Just done that and the download has now started without issue…thanks for your help Hopefully it completed but couldn’t even get it to start without Ctd so I assume it will be ok