Bi-fold doors need regular adjustment to work properly. The doors are not hard to adjust, but it seems to be a game of constantly fine-tuning the doors.
The key is to get the doors to the point where they have a uniform gap in the middle, and that they fully open and close without getting hung up on anything. To accomplish that you have to make some fine adjustments.
Look and see where the doors are contacting each other. Is it the top or bottom or all along the entire length of the doors? There are adjustments at the top and bottom of each door on the wall side. At the bottom of each door is a pivot that sits in a grooved bracket. This allows you to move the doors closer to each other or farther from each other. You simply lift the door and move it to the next resting point in the bracket. That adjustment will give you some space in between the doors, but you will also have to adjust the top of the door as well to keep a uniform gap between the doors.
For this adjustment, you will need to open the door. The top of the door has a retractable pin that slides into a guide in the track. There will be a screw you can loosen that will allow the guide to slide down the track. You need to make small adjustments until both doors work correctly. You will see a pattern of adjust and test. Once you have the doors to your liking, be gentle with them. You don’t want to have to do this every week.I Have to Push Hard on My Door to Get It to Latch » « Caulking Baseboard Before Painting