What you’re doing is kind of tricky. There’s no global setting where you can tell Windows, “Install new stuff here.”
It also depends on the program that you’re installing.
The other issue is that you’re somewhat defeating the purpose of the SSD by not installing your software on it. This is the drive where your machine can load files and access programs more quickly than if they were installed on a traditional hard drive.
In your case, there are two things that I suggest you do.
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Installing applications on a drive other than C:
Install location is a per application kind of a thing. When you install software, always choose the Custom or Advanced option. That’s where you can specify to install software at a particular location if that program’s installer is set up to allow you to do so.
It’s important to understand that Windows will still install some things on the C: drive. Again, this depends on the specific program.
Why? Sometimes, it’s related to application sharing and complexity, but some programs have components that get installed on C: no matter what.
Cleaning up C:
In your scenario, the real issue is your C: drive. What I recommend you do is clean it up.
Installing programs on C: is what you want, but I would look at some of the other things that are going there. Start with my article, “Where’s my disk space going?” which will actually show you what’s taking up space on the C: drive and what might possibly be cleaned up. Depending on what you find, you can then remove data or perhaps move data if the programs involved can handle that. You might also use a tool like CCleaner to clean up files as well.
Moving temporary files
After you run the tools, I’m going to suggest that you move your temporary file folder. Now this is a bit controversial when it comes to an SSD because the point is to read files more quickly.
Unfortunately with temporary files, they’re being written often and may be taking up space. SSDs don’t necessarily write much faster than hard drives and temporary files can slowly end up taking a lot of hard disk space.
Now, if you don’t want to move things to the other drive that you have, my only other suggestion would be to simply run CCleaner on a regular basis to make sure that things are cleaned up regularly, and perhaps uninstalling programs you don’t need. That way, you’ll be maximizing the amount of space you have available on your C: drive.
Other than choosing when you run the setup program on a per application basis, there really isn’t a way to do exactly what you’re asking to do. You just have to pay some attention to this as you install software.