Hi brucegrund, we had this issue of the zips an extracted files seeming to be broken once downloaded, usually caused when packages are shared and the links are bundled into the share.
If there are no links unzip works fine
For us they actually aren't broken but they are ZIP files within ZIP files when you have LINKs in your models. You need to extract both levels of data. First unzip will show .RVT, change RVT to ZIP and then extract, you'll then see the links, you can then successfully open the files
Hopefully this was your issue to 🙂
