Yes, I've never had a problem opening past projects I have over a hundred in my active folder and I switch every day.
The new hise project opener UI is likely what has caused confusion. There are many things you could've done wrong / misunderstand about the way hise projects work, so it's hard to know exactly what has gone wrong for you. The interface for loading projects is very new and didn't use to exist. It probably gives the illusion that the hise saving system works like any other software, but in truth it's a bit more manual work. Different saving options in hise save different parts of a project. Some overwrite, some create copies, some save only the scriptnode networks some save only the structure of the project, etc etc.
It's something I only figured out myself after making mistakes, and manually reading through the files that hise saves.
Create a new project, save the xml.
Now create an additional new project, and save the xml.
You should now have two different folders which bear the respective project names.
To load in one of the new projects, use the load project option and navigate to the first layer of a projects folder. Hise will then open the project using all the project files it's not just the xml or hip that it uses.
