First of all: Blocs 4 is SUPER! I’m very happy with ist. Many thanks to Norm and the team!
But be careful with one setting in “Project Settings”. Now you can select the Export Location. When you for example choose the desktop and you export a project, you will be asked, if you want to overwrite everything. And if you click “yes”, everything there is overwritten, means deleted.
My second thanks go to the inventor of time machine 
I think that should be reported as a bug. Reporting Bugs – Blocs – User Documents
I am sure @Norm would want to patch that somehow a.s.a.p. It is surprising that this is affecting the whole desktop and not just a specific folder, but good to see this made known.
It’s because the Desktop is a folder. You need to create a folder within the desktop with the name of the project and select that.
Maybe I should create a block list so some paths cant be used.
I would always designate a specific folder, not least because it would otherwise scatter the various export content but I can see how some would make this error. A block list sounds like useful idea.
Yeah I’ll try and get it out asap.
Reading the opening post I was like … “Well, yeah, that’s how it’s supposed to work”. And you even get a warning… not sure if setting a default location would help to prevent that 
