FCPX 10.4 crashes upon opening in high sierra

I hope someone can help me with a problem. I am running FCPX 10.4 on a 2013 6 core Mac Pro with High Sierra installed. I have been editing a video the last couple days but yesterday evening when I turned my machine on to make more changes to the same video it crashed while loading the library and project. It now happens every time I attempt to open the program.

I am noticing in the splash screen when you first launch, there are no plugins, etc loading. in other words I am accustomed to seeing small code script, plugin titles flying by underneath the FCPX logo as the software loads, indicating all the necessary plugins and ad-ons are loading as the program prepares to open.

since yesterday, now all I get is the splash screen showing FCPX 10.4, then I get the windows of the program with clips, timeline, view etc. then it crashes as its re-rendering the project.

HELP

For starters, to get FCPX running again, launch the program while holding down both the COMMAND and OPTION keys. Choose to delete preferences when asked. This should bring up FCPX and you can then try to open your library. Before you try opening the library, go into FCPX preferences and turn off BACKGROUND RENDERING under the playback menu. This gets turned on by default when clearing fcpx preferences. If opening the same library causes another crash, then there would appear to be an issue with something in the library, project or event. In that case, repeat the above to trash preferences and upon opening FCPX, try to open a different library. If that works you can try to open a backup of the original library that was causing the crash. Report back what results you get and we can go from there.

Hello

thanks for your response. yesterday I'd tried deleting preferences to get FCPX to open with great success. I was able to open other libraries and projects BUT the one in question was still causing problems and would crash the program.

In the process of creating the project I had made a lot of changes to one specific lower thirds graphic, swapping out different version from the "Titles" library, changing fonts multiple times over the course of editing. Because of that I determined that maybe that particular lower thirds title had become corrupted in the timeline. I deleted it and started from scratch, which seems to have fixed the problem.

thanks again