Final Cut Pro X 10.4.2. Damaged library.

Hi guys. I am at the end of a project and of all of a sudden fcpx crashed and the computer restarted itself.after reboot,i launched fcpx and got this message {Library appears to be damaged} open a backup version or continue working,fcpx will no longer back up this library.
I chose to use a back up and same thing happened again.after a couple tries, i got it to work but ,it seems that i have to create optimized and proxy all over again.any help??
My external drive still have plenty of space in case you're wondering.

Go to your Movies folder, to the Final Cut Backups folder. Find a copy of the backup that's not corrupted.

Yes, you may have to recreate proxies if the crash was bad, but that can happen in the background, and shouldn't be too huge of a problem, compared to losing everything completely.

thanks.I guess that's my only option Huh.My next question is , what to do to prevent this from happening in the future? is it even avoidable?

Regulare maintenance. I don't think I've ever seen FCPX crash and cause a Mac to reboot. I suspect something is not right there. But here's my recommendations.

Every night I run automated backups.

Once a week I run First Aid in the Disk Utility app, and verify that all my drives, especially the system drive has at least 20% free space. I also use Final Cut Library Manager from ArcticWhitness to trash all render files from all of my Libraries.

Once a month I run Disk Warrior, although we're still waiting for it to be updated for macOS High Sierra AFS drives.

But I'm suspicious of an app causing a system to reboot, that's highly unusual, and could be a symptom of some other issue. We'll have to wait and see at this point.

All these problems have started since i updated to HIG SIERRA. I kinda blame myself for not doing a clean install despite all the warnings.
I will follow your advice and do just that. thx.
For the past two weeks ,my MAC crashes and reboot at least 5 times only when i am using FCPX tho.

Hi xtra
Sorry to hear about your issues, but you really need to get to the bottom and fix the issue if it is causing kernel panics (full shut down and reboot) Not good

Fortunately, Apple provides help here via crash log files. It can get complicated to understand what the Crash Reporter logs mean, but it may point to a simple fix for the issue. It will provide the info on where to look.
Instead of me writing each step, see these articles…

This one is very good step by step to finding/opening log files and some interpretation.
www.maketecheasier.com/read-macos-crash-...ts-troubleshoot-mac/

This is a simple explanation of what to look for.
www.macissues.com/2016/04/12/using-the-o...e-a-program-failure/

And here is Apple's developer take on reading files (I think this link is open to non-developers)
developer.apple.com/library/content/tech...s/tn2151/_index.html
Little harder to decipher, but more complete.

Once you see what is causing the crash, you can try to remove the file, plug-in, cache, etc… that is causing the issue.

I suspect that you have some corrupted file or maybe a (FCPX) plug-in that is incompatible with the OS. Make sure to update plug-ins and apps.
You might also download and run EtreCheck for possible problems/solutions. This helps interpret system diagnostics. You can use it free for 5 times per download. Decent tool.
etrecheck.com

If you still can't figure it out, copy the portions of the log files showing the crash thread and I or someone else might be able to suggest a fix.

Anyway, Hope this Helps, Greg

edit: I personally recommend to always do a "Clean Install" when doing a major OS update. Cleans out the crud. I never use Migration Assistant.

Thank you for your helps.I'll try everything suggested and hopefully the problems will be fixed.

Same problem Happened again using FCPX. Here is the crash report. I don't know what to look for in the crash log and was hoping if anybody in here can take a look at it and please tell me what do? I"d greatly appreciate it..thx in advance.