Final Cut Pro X 10.3.4 (!) on High Sierra - crashing

This thread says you need to launch FCPX with the laptop open:

Final Cut X (10.3.4) crashing on external display

https://discussions.apple.com/thread/8087074

Does that work?

Are they still in the correct location? Have you contacted the developers?

I'm finding it incredibly surprising that people using large numbers of plugins are installing a brand new OS on the first day of its realize, especially if they're in the middle of a project.

Yes I followed that advise too after disconnecting the monitor it works. I have the LG utlrafine 27" 5K monitor.

Seems like I have to disconnect the monitor, open final cut pro, then connect the external monitor back on again.

*****...

That is exactly what I did and it worked, that being said I don’t really want to have to do this every time so I wonder how to fix this. It would be nice to just have monitor connection with my MacBook and everything works like it should.

I had a similar experience, maybe this will help -

After updating to High Sierra I couldn't get any library to open in FCPX at all. After a bit of trouble-shooting I discovered that it was all to do with my A/V Output (I have a Matrox I/O & a Blackmagic Intensity Shuttle). After disconnecting all of my external A/V sources, FCPX again runs like a charm.

No client monitor or monitor speakers at the moment but I'm guessing that this is just a case of Matrox/Blackmagic updating their drivers and will be fixed soon.

Same issue, except not using an LG external display. I am using two Dell 4K monitors with USB-C to HDMI adapters. Disconnect the monitors, start Final Cut works perfect. I can even reconnect the monitors and it keeps working. Very irritating, but it works at least. :-/

I took my High Sierra out after one day and went back to Sierra so I could use my Final Cut Pro X, I am not going to pay $300 for a new program to Apple, I also noticed my iMacs and Mac Book Pro working slower with HIGH SIERRA, bad choice.

No reason to pay another 300.

It is likely that a new update should come soon with better HS support. All updates until now have been free.

In the meantime, it staying with Sierra seems a reasonable choice.

Recover back to Sierra, I did that and have Final Cup Pro X working great, unless you want to buy the program again for $300, to use High Sierra. I also found High Sierra to run a little slower, my 3 Macs have 16 M of Ram !.

“unless you want to buy the program again for $300, to use High Sierra.“

You never have to pay for the application again regardless of what OS you’re using.

Most professionals are reporting that HS is faster than Sierra. Depending on what you’re doing VRAM is probably more important than RAM.

Everything that I explained happened on the following Mac with the following specs: MacBookPro13,3 with Intel Core i7, 16GB 2133 MHz LPDDR3 and Radeon Pro 460 with 4GB VRAM.

I think External Display issues have been common for a while. I noticed that the LG Ultrafine 5K Display had issues on macOS 10.12 while using a program called OBS and at times when trying to changed the audio settings. Final Cut X did not have issues with 10.12 Sierra, but now fails with 12.13 High Sierra while using any external displays. I have two Asus 1080p displays at my workplace and the LG Ultrafine 5K Display at home.

The workaround for now is to open the MacBook Pro's lid and wait for Final Cut X to open and load the library properly. Then the lid can be closed afterwards.

I suppose I can use the workaround for now, but you know Apple's motto: Apple devices "Just work". Considering I paid over 4k for my MacBook Pro, I would like to think these type of issues should not be part of the experience a customer should worry about for extended periods of time. Let's hope Apple is able to resolve the issues and keep the faith customers have put on their products going.

I've got the same problem. 13" 2015 MBP, fresh install of High Sierra (release version). Installed FCPX v3.4. No external display. Create new library/event/project. Import a few clips from a GoPro H6 (which remain on their USB3 external HD).

Select the clips in the media window. Select Create compound clip. Enter name for compound clip. Return. CRASH. 100% reproducable.

What exactly does my workflow have to do with anything? I create a compound clip because my footage is comprised my multiple small clips coming from an action cam, i.e. multiple 8 min clips creating a 2 hour stream.

What exactly do my pref files have to do with anything? Did you read what I wrote? I said the crash occured after a 100% fresh install. Fresh OS, fresh FCP, fresh library, fresh event, fresh project. So what preferences exactly could be corrupted here?

Normally user assembly their material in a project.

Trashing prefs is fine because 95% of the times if the application crashes the preference files will be corrupted because they were saved correctly during shutdown.

You may also have a conflict with other software, or the external drive isn’t correctly formatted or needs updated drivers.

But whatever.