FLStudio 20.0.4 [Running on my crappy laptop] and 20.0.3 [Running on my very high end PC] (Yes I know these are not the latest versions) have been doing.
When a project file has been altered and changes were not saved ...
project.zip
If I delete both the zip and zip~ files and then export to zip again I don't get this error.
Is this how I should be working? Is there some more intuitive way in FL to collect samples? ...