When exporting a .csv file from your favourite Property Management System (i.e. Property Tree) if file automatically opens using Excel you will need to turn this setting OFF so it doesn't interfere with the processing PIM needs to perform on the file.
In Chrome can you tap the 3 dots (top right) > Settings > scroll down bottom to Advanced > scroll down to the "Downloads" Header> then tap Clear where it says "You have chosen to open certain file types automatically after downloading".
After changing this setting try exporting the .csv file again from your system (ie. Property Tree > Export all to .csv) and the file should just save to your downloads directory or ask you for a preferred location. It should not open the file.
Email support if it continues to open the file automatically.