i have a project I have edited. fop crashes in one thread and I do not know how I can fix it. I use MBP 15 i7 radeon 560 early 2016 and tried under MBP 2018 i7 Vega 16 with the same log-info for the crash thread. can anybody help me please
It is apparently crashing when doing database operations in the library. FCPX uses SQLite as the persistent data store. It is normally very reliable and has transactional integrity that protects against data loss from aborted transactions, app or OS crashes, etc.
Under what conditions does it crash? Is it reproducible when doing a certain action? You might be able to create a new "salvage" library, then drag/drop the problematic project to that. However always do this inside a "transfer event", not the bare project. Create a new event in your main library, drag/drop the project to that, then drag/drop that event to your new salvage library. After that click the new library and pick "consolidate" in the Inspector.
This also copies all media referenced by the project. If that works open the project in the new library, examine the timeline and see if your last edits are there.
It could also be caused by a plugin. In your original library create a snapshot of the problem project via right-click>Duplicate as snapshot. Open that snapshot copy and see if it looks OK.
Each project (inc'l snapshot copies) create a new SQL database within the library called CurrentVersion.fcpevent. SQLite may do certain data validation checks when inserting the rows into the SQL tables in the new project. However the database does not understand higher-level application-layer constructs. If FCPX has stored invalid or malformed data in the tables of the original project, this might be copied to the new snapshot. But it's worth a try.
If the snapshot copy crashes or shows any problems, select all clips in the snapshot timeline via CMD+A then remove all effects with Edit>Remove Effects. See if it works then. If it works then repeat the procedure but delete FX from half of the timeline each time until you find what clips and effects are causing the problem.
It also doesn't hurt to check the usual things: plenty of available disk space on all drives, run Disk Utility First Aid on all drives, reset FCPX preferences: support.apple.com/en-us/HT203477
Verify all libraries and all media are on HFS+ or APFS partitions, not exFAT or NTFS.