14 Replies Latest reply: Dec 31, 2012 12:59 PM by riesje
Darfuria Level 1 (0 points)

I'm having a frequently (but still intermittent) issue where FCP X crashes when rendering a video (at around 12% completion) when FCP is set to use optimized/original media. If I render using proxy media, the crash doesn't occur, but obviously the exported file is low resolution.


Once FCP crashes, the project tends to become corrupt and the application will crash again upon launching unless I remove the project.


I'm using a 2010 2.4Ghz i5 MacBook Pro with 8GB of RAM, and a FW800 scratch disk.


  • I have successfully edited & rendered 50+ videos of 1080p videos. Neither the type of source footage, length of projects, or my workflow have changed.
  • I was using 10.0.3 prior to upgrading to 10.0.7 - I didn't have any problems using that. I've perhaps successfully rendered 40% of my projects since the upgrade.
  • I have moved the events & projects to different drives
  • If I remove a project after a crash, the application runs smoothly and I can scrub through the event media
  • If I'm using proxy media (which is what I edit with), there's no issue. I can also render proxy media
  • I've used Digital Rebellion Housekeeper, QuickFix, and Project Repair - no corrupted projects were detected even when FCP is crashing upon launch
  • Crash Analyzer reports that 95% of the crashes are due to Corrupt Thumbnail Cache. I have deleted this many times, and I edit using the simple clip view (no thumbnails or waveforms). The others are due to motion effects - the only ones I use are fade transitions, and occasionally speeding up video. Nothing third party.
  • I've deleted and re-imported event media.


I'm kind of confused as to where to go from here. The problem seems intermittent, but it's getting worse. I had a project that crashed when rendering, and FCP wouldn't launch until I removed the project. After that I managed to edit & render another project with no problems. Then the project after that crashed during rendering and caused the same problems. The source media from these projects was shot on the same day as other clips that have been successfully edited & rendered.


Any tips welcome!

  • Ian R. Brown Level 6 (18,615 points)

    I see you have used some of Digital Rebellion's apps but you don't mention whther you have trashed the preferences using




    Corrupt preferences can create a vast range of different symptoms, so whenever FCP X stops working properly in any way, trashing the preferences should be the first thing you do using this free app.



    Shut down FCP X, open PreferenceManager and in the window that appears:-


    1. Ensure that only  FCP X  is selected.


    2. Click Trash


    The job is done instantly and you can re-open FCP X.


    There is absolutely no danger in trashing preferences and you can do it as often as you like.


    The preferences are kept separately from FCP X and if there aren't any when FCP X opens it automatically creates new ones  .  .  .  instantly.


    If that doesn't have the desired effect try deleting the app with FCSRemover and reinstalling it.

  • Darfuria Level 1 (0 points)

    Sorry, I forgot to mention I had trashed the preferences and reinstalled the application the traditional way.


    I have just trashed the preferences through PreferenceManager and uninstalled using FCSRemover. Unfortunately the problem is still occurring.

  • Ian R. Brown Level 6 (18,615 points)

    I am a little confused by your term "rendering".


    Are you referring to the rendering that occurs in the background and can be viewed on the Background Processes monitor or do you really mean that the crashes occur when you are exporting to something and FCP is encoding/transcoding rather than rendering?


    If so, exactly what are you exporting from and to?

  • Darfuria Level 1 (0 points)

    Sorry - exporting. Background Rendering is disabled. The crashes occur when I export a project.


    I'm not entirely sure what you mean by "from and to" - I am using a FW800 scratch disk. The event & project files are stored there, and the projects are exported to that drive as well. I have moved events & projects to other drives and have experienced the same issue.


    I edit with FCP set to use Proxy media, then switch to Optimized/Original when I come to export. I usually export using a Compressor destination I have configured, but have switched between that and using FCP's export settings for web, and have tried changing between 1080p and 720p.


    It might be worth noting that I tried to export whilst still using Proxy media, and that worked fine.

  • Ian R. Brown Level 6 (18,615 points)

    Why are you using Proxy Media?


    Unless your projects are extremely complex it should not be necessary.


    If possible try editing either the original media (AVCHD?) or ProRes 422.

  • Darfuria Level 1 (0 points)

    My MacBook drops frames/runs too slowly when I edit optimized media or the original media.

  • Ian R. Brown Level 6 (18,615 points)

    I would suggest that there is probably something wrong with the computer.


    You shouldn't be getting dropped frames unless you are editing highly complex projects containing numerous multi-tracks or  loaded with special effects etc.


    It is quite possible your hard drives are too full or fragmented or that your Mac just needs some basic spring-cleaning.

  • Darfuria Level 1 (0 points)

    Whilst I can't deny that being the case, it's entirely acceptable that a machine of this spec cannot playback raw 1080 50p footage. Furthermore, I have been successfully editing videos of this footage using this same workflow for a number of months now, and these problems have only just started occurring. It seems unlikely to me that there has always been an issue and it has now gotten worse and is causing FCP to crash in this way.

  • Ian R. Brown Level 6 (18,615 points)

    Quite the reverse.


    To take just one example, if the problem lies with over full or fragmented hard drives, the problem will become worse as you edit and vast amounts of files etc. are being added continuously.


    You should have no hard drive more than 80% full and the system HD should have as little as possible on it.


    Open Disk Utility and run Repair Disk Permissions and Verify Disk if you haven't done it recently.

  • riesje Level 1 (0 points)

    I'm having exact the same problem. Used disk utility to no avail. All disks are fine. Never had a problem with FCP X. Since three days it just wont export a very simple 2 min movie with some photos. Tried every export on every setting for three days. No luck. Big trouble here.. need to get working.

  • Darfuria Level 1 (0 points)

    I've used multiple scratch disks at different capacities - my main one is about 40% full currently. The system HDD has about 30% free space, too.


    I repaired disk permissions a little while ago, and verifying the disk reports no problems.

  • digibudII Level 2 (415 points)

      I would ask how you moved those files when you say you moved projects and events to another hard drive.   I found out that if you simply copy those folders to another drive you can cause all sorts of issues. I did that early in my FCP days and finally had to abandon the project entirely. There may have been a fix but I could not find it. I could not move it back to the original drive and it would lock up FCPx at some point when I tried to use it.  You have to copy/move projects and events from within fcpx.

       If you are moving and deleting projects from within the Finder as opposed to doing through FCP menus, then I would suspect that is the issue and if your experience is like mine you may have to start those projects from scratch.

  • Darfuria Level 1 (0 points)

    I've moved projects and events through finder before with no problems, but I hadn't moved these projects or events prior to the crashes occurring, so me moving them can't be the cause of the problem.

  • riesje Level 1 (0 points)

    I'm having the same problem. Crashed and crashes. I'm always moving stuff in FCP menus, never in the finder.

    thanks for your help anyway.