problems with Microsoft and downloading.

In Jan & Feb I downloaded 3 files for using in our Zumo 660 ad 220. I Downloaded OSm Generic windows for Spain, France and Portugal.
I transferred them into a Garmin, Maps file and have been working in Garmin Basecamp on routes.
Ive successfully loaded both the maps and routes in the Zumos.
Then this month I tried to down load the same generic windows maps for the UK. Each time I a told that the file is either corrupted or Microsoft cannot open this type of file.
I tried the new versions of the maps and then tried a few segments of the maps. Same result.
So then I tried downloading the zip file with OSM,
It downloaded but when I unzipped to the SD card directly. Noting opens and it states the file is corrupted. the version is 19-3-2018


Any ideas

Which Garmin suitable map download service did you use:

this one

That would be from this site:
Sorry, I can’t offer a solution. It seems you may have already tried the manual selection method with the same result.