Export stuck at 49% of the project

Version 10.8.1 of FCPX on my Mc Book Pro Sonoma 14.2.1 is not exporting entirely a project. It is stuck at 49% and doesn't move from that point. I can export in two chunks so there is no corrupted file or missing file disturbing the process. It only doesn't work when exported in one chunk. Disk space is ok and generally the system lets me know when there is not enough space on th disk. So, what could be the problem. Thank you for helping if you can.