Insufficient disk space on Elements 2021 despite 20G + free?

[RickardE]

Getting the insufficient disk space error even though I've cleared up 23GB free on C:.
All the other drives are well over 100 Gb free.

How much is really needed? 
I've cleared up the temp-folder, uninstalled unnecessary programs och run CC. Still no luck

Any ideas? 

Trying to install both:
PhotoshopElements_2021_LS30_win64
PremiereElements_2021_LS31_win64

[Test Screen Name]

Does the mention specifically mention "scratch space" or "scatch disk"? 

If, large images or complex edits will use 20GB in no time at all. This is a system about to fail, if it is so full.

If you have other disks you can choose one or more of them to use instead, for scratch space, in Preferences.

Or... is this message happening during install? Then the disk really is filling up.

[RickardE]

This is happening when I try to start the installer. Regardless of what hard drive the installer is on I get the same message.
Was planning to use a different drive as scratch disk when I've completed the install but I can't even start the *.exe 🙂

[Test Screen Name]

Installers need a good deal of space on C, for temporary files and common files, even if you get the chance to install the app somewhere else. There is a fashion among PC makers of giving a tiny C drive, but it's a disaster.

[RickardE]

Kinda sucks but I guess that's life... 100 Gb hard drive that ONLY has win10 on it can't install photoshop because it lacks disc space... Horrible 🙂 
Thanks anyway