I am thinking of update from Cubase 9 Artist to Cubase 13 Artist.
My main drive only has 1.3Gb free space and spec says 13 requires 75Gb free space.
Is it OK to move the installed version of 9 to another drive to free up space on C:/ ? Or should I uninstall 9?
You need a new drive altogether. A drive should never be more than 90% full.
I have 150 Gb free on my C: drive and I’m already thinking of getting a bigger drive.
In 1998 when Unreal came out 1.3GB was much disk space but I’d say for today’s standards even your OS may get into trouble running smooth.
My suggestion is to free up some space on your main and install Cubase 13 there. Then install another drive or attach an external USB drive and install all the Cubase libraries to that drive, which make up the majority of the xxGB. Also you need space to store new projects, where the additional drive would be neccessary. And if your othere sample libraries are on the main drive move then to the new drive too. Then you can leave 9 installed if you need (but of course 9 will still need the dongle, Cubase 13 does not)
To be pedantic, the libraries etc are not necessary and are optional, and are only (!) 35 Gbs. The rest of the requirement is so that they can be downloaded and then installed.
Just install the Cubase executable.
Cubase 13 Pro is 700 MB so it is just about what you choose to install. Cubase 9 and Cubase 13 run independently of each other so you could have both installed or uninstall v9. I think the better option if you upgrade is that you install the library files to another drive.