FCPX crashes and the library lost the location when I try to duplicate projects.

In addition to Tom's questions, if the library is stored on an external drive, how is it formatted? The drive must be either HFS+ or APFS. Format storage devices for Final Cut Pro, Motion, and Compressor - Apple Support

Where is the library stored? How much free space in your drives?

Please post an EtreCheck report https://etrecheck.com giving the application Full Disk Access in Privacy & Security Sysyytem Settings. Copy the report and use the Add Text button to paste the result into reply box. 

We've been dealing with this problem for quite some time. I believe the problem was exacerbated when 10.7 came out. We have six edit system connected to a GB Labs NAS. The NAS runs on SMB. When the FCP Library lives on the NAS the library will corrupt itself when you attempt to duplicate a project, which we do 50-100 times a day in our particular workflow. The only workaround for us was to keep the Library on each editors local machine. This introduced quite a bit of complexity and the opportunity for lots of problems but we manage.

I've posted "Final Cut Pro Feedback" to Apple on multiple occasions over the years, even in person at the FCP Summit, but still the problem persists. It feels like the FCP Library only likes to reside on APFS or HFS formatted drives on a macOS system.

We have 3 edit systems that work off libraries stored on QNAP 10GbE NAS systems that are mounted as SMB volumes. I have encountered over the last 5 years maybe 3 or 4 times that a project could not be duplicated or snapshotted. We're still running 10.6.5 on Ventura.

Recently I tracked down the cause of a failure when trying to duplicate a project. Copying the entire timeline and pasting into an empty project would also immediately fail with a system beep. After dividing and conquering, I determined it was a retimed compound clip. I excluded it from the copy and it pasted into a new project timeline without issue.

I have not heard of GB Labs, but perhaps someone on the LiftGammaGain storage forum can provide insight. Bob Z in particular is very knowledgeable and may know about required hardware-specific configuration settings.

That’s correct. FCP only works on APFS or HFS+ formatted drives.