Windows 10
To prevent the download occurring go to Tools > Program Settings and set Automatically Start Downloads to NO.
Can you access the path %localappdata%\Logos and open the folder Install\Installers? You could try to run the .msi file directly.
If I do that, it just reinstall the original but then same issue with the update.
It is a good idea to describe your problem in detail, together with version of Logos and OS..
But taking your response at face value, go to https://support.logos.com/hc/en-us/articles/360008551751-Error-Writing-to-File