The folder WIN64 is over 30GB. I’m not sure what’s the deal here with all these subfolders, downloaded with Steinberg Download Manager, residing in this directory:
C:\Users\username\Downloads\Steinberg\WIN64
Can I safely delete the content of WIN64 folder, without screwing up any Steinberg installations?
That folder contains the downloaded installers. Of course you can delete it, it has no impact on the installed software.
However, if you want to reinstall some software the whole download process starts again, because the Download Assistant can’t find the packages on disk anymore.
You can change the download location in te Download Assistant to some external disk and then keep all packages there.