How to recognize and fix 11 common problems in Final Cut Pro X

There is an old saying that I really enjoy. Some things are like the ocean: shallow enough for a child to wade in, yet deep enough that you will rarely see the bottom. Final Cut Pro X is close to one of those things… until you feel like you are drowning.

My 10 year old son is perfectly at home using FCP X to edit Lego videos, and as an editor I have yet to reach its depth. But when FCP X isn’t behaving as it should, you may start to feel that drowning sensation. If that is the case, this article series is for you. Based on my experience working alongside hundreds of FCP X editors —on everything from Bollywood features to corporate films—I’ve come up with a list of the top symptoms and their fixes. In this first series are the top symptoms related to FCP X data corruption, including an overall note about how to prevent getting into trouble in the first place.

Symptom #1: Yelling and screaming. Complaining about #FCP X on Twitter.


Complaining about FCP X on social media could indicate you need to learn more about the program.

Diagnosis: It might just be improper expectations

First of all take a deep breath. Many of us have been there. You might have a real problem, or it might be that your expectations are a little off. Apple really did rethink the NLE when they designed this editor and for many folks it operates so differently from previously NLEs that it’s hard “to unlearn what you have learned”, as Yoda would put it.

Prescription: On one level FCP X is so easy your kids can easily edit with it, but if you are a seasoned editor, or even a new one, and your livelihood depends on FCP X, invest the time to thoroughly learn the app. A simple way to accomplish this is to read the FCP X User Guide. People look at me weird when I suggest it, but it’s one of the best kept FCP X secrets.  It isn’t perfect and  it isn’t meant to be a how-to guide for editing, but it will get you familiar with all that FCP X can do. I keep the iBooks version on my iPhone and try to read a chapter at a sitting. You’ll be shocked at how much you learn, and how much more you can do with FCP X. Second, watch  or read some high quality training. Ripple Training is excellent. has some good titles as well. As does Larry Jordan. The Apple Pro Training Series books on FCP X are also excellent. 

You can find the user guide and links to training here.

Symptom #2: A function stopped working, or is performing strangely, or FCP X crashes.

Diagnosis: Possibly corrupt FCP X preferences (very common)

Prescription: If you are seeing new puzzling behavior in FCP X, resetting your preferences is the first thing to try. Especially if the software has crashed on you, because a crash can cause the preference file to become corrupt, and a corrupted preferences file can cause FCP X to crash.

Digital Rebellion Preference Manager is an excellent free tool to save and restore fresh preferences or you can use FCP X build in function. For the latter, quit FCP X, then hold down command-option while clicking on the FCP X icon. You’ll be presented with a dialog box; click “Delete Preferences” to reset your preferences.


Not everything can be fixed by deleting preferences, but it resolves a lot of odd behavior.

Resetting preferences is a quite safe. However, you will lose a few bits of customization, the most unfortunate being custom naming presents. The few items in preferences will be reset: general, editing, and importing; as well as Browser column settings. But Your Share Destinations, Effect presets as well as audio effect presets will all remain intact.

Symptom #3: Timeline won’t render and/or share. Crash during playback of rendered area.

Diagnosis: Possible corruption of FCP X Generated Render files (very common)

Prescription: Select the Project in the Browser and choose File > Delete Generated Project Files. You can start with just the unused items, but if you have further trouble it’s probably best to delete all files. Generally you won’t need to delete Proxy or Optimized media. If deleting render files for the Project doesn’t resolve it, you can select the Event and choose to Delete Generated Files for the Event, or even the Library.


Render Files in FCP X seem to be particularly susceptible to corruption. If trouble arises with rendering or export deleting them should be your first action.

Rendering Tip: For my workflow, 9 times out of 10 I don’t ever render in FCP X. FCP X performance is amazing, and in most cases sharing (exporting) an unrendered timeline is several times faster than the time it takes to render and then share.

Symptom #4: Library that refuses to open. Event icon missing. Inability to share Project. Inability to render timelines.

Diagnosis: Possible FCP X Library corruption (less common)

Prescription: If you can open a Library, try moving your Events to a freshly created Library. Oftentimes this can resolve the issue.

If you can’t open the Library, you can attempt to remove some specific generated items inside the “root level” of your Library bundle. I have found removing “CurrentVersion.flexolibrary” as well as “Settings.plist” is safe and can often get a Library to open.


Removing these two files from a Library Package can often resolve problems with opening a Library or when an Event icon goes missing in a Library.

It is also possible that a Library won’t open because of a corrupted Event database. Moving out individual Events out of the Library may make the Library able to open again, and point instead to a problem Event, or even timeline. I’ve seen a few Libraries become so corrupted that you must resort from a backup. By default your libraries will be backed up to “Final Cut Backups” in your User’s  Movie Folder. The backups are  organized by folders by Library name with timestamped Libraries inside the folders. Just double click the backup Library of your choice and FCP X will walk you through the restoration process. 

If you’ve tried these options, including restoring from backup, and your Library still won’t open it could be a corrupted media (see Symptom 7 below) a corrupted plugin (see Symptom 8) or corrupted user account (see Symptom 11).

Symptom #5: Inability to share Project timeline, inability to render. Odd editing operations.

Diagnosis: Corruption of FCP X Project timelines (rare)

Prescription: You’ve got a few ways to tackle this. It’s best to do the following in order:

  • First, try moving your Project timeline to a fresh Event and then a fresh Library. Check whether the problem is resolved.
  • Second, If those doesn’t fix it try copy and pasting all the contents of a timeline to a new Project Timeline that you created in a fresh Event.
  • Third, If problems still persist you can try to copy and paste portions of your timeline in chunks.
  • Finally, If this doesn’t resolve it, exporting an FCPXML. Reimporting to a fresh Event and/or a fresh Library should resolve any corruption that might have happened in the timeline. You might lose some minor portion of your edit, especially in 3rd party effects or transitions, but this is a small price to pay to bring back a Project timeline from the dead.

Symptom #6: Inability to import footage. Can’t render or export Project timeline.

Diagnosis: Corruption of FCP X event (rare)

Prescription: There are two main ways to resolve this.

First, copy the contents of your Event to a freshly created Event within the same Library, or secondarily, try a fresh Library.  If copying doesn’t work, try an FCPXML export and reimport. First to the same Library, and if that fails, to a new Library.


If other things fail exporting a FCPXML and reimporting to a fresh Library or Event can save your bacon.

Symptom #7: Not being able to open a Library or even a Library backup. Inability to render a section. Share fails midway.

Diagnosis: Corrupt or improperly formed media files (rare)

Prescription: Finding that one piece of the bad media can be time consuming, but you gotta do it.

If a share or render fails midway, FCP X may give you a frame number where the error occurred. When you see this, open Preferences (command + comma), flip your time display to frames, and you can quickly locate the problem media. If you didn’t get a specific frame error, share just a portion of the timeline by selecting a range, and then continue to work to narrow down the troubled clip.

When your Library won’t open at all, “hiding” the media may help determine if it a piece of media that is the problem. If you’re using external media hiding should be straightforward, but as you probably know, FCP X does an amazing job of finding media that has been moved. It’s best to disconnect the drive where your media is stored. If hiding your media does resolve your issue, try hiding just portions until you can narrow down the culprit.

If your Library won’t open and you are using using managed media, you’ll need to locate the original media stored in each Event. Rename your media folder by adding an “X” to the beginning or end of the “Original Media” folder to render it disabled by hiding it from FCP X. Disabling media folders Event by Event can help isolate the problem clip.

Symptom #8: Crash or hang when opening a Project timeline, Crash when using specific a specific plugin, kernel panic, extreme slowdowns.

Diagnosis: Corruption of FCP X plugins (very rare)

Prescription: Third party plugins, especially FX Plugins, add great capabilities to your toolset but can bring FCP X to a crawl. These symptoms could also point to issues of overloading FCP X which I’ll cover in the next article in this series. As of FCP X 10.2,3, plugins are used only when the clip that contains a given plugin is accessed or played. Therefore attempt to isolate the clip where the problem occurs to narrow down the possibilities of problematic plugins. Sometimes however, you are unable to load a Project Timeline because simply accessing that plugin causes a hang or a crash. If that is the case, disable everything and slowly add items back.

FXPlugins are made by many talented FCP X developers who don’t want their plugins to cause problems. Thus I would encourage you to contact them about the issue. While you are waiting, you can temporarily move the FXPlug Plugins to another location. Find them here:


Motion templates rarely cause issues, but a corrupted file in a motion template can cause issues. To troubleshoot rename your Motion Templates folder in your home directory Movie folder. Placing and X is a great place to start.

Audio Units issues are very rare, but if you need to you can move them to a temporary folder from their normal location at:


Symptom #9: Crash when using titles and/or a specific font.

Diagnosis: Font corruption (rare)

PrescriptionIf you have download free fonts from the internet, for example, font corruption is a great possibility. Many free fonts are improperly formed or simply corrupted. I’ve seen bad fonts crash many an app.  Using your font manager, or Font Book, disable your “non-system” fonts and see if the problem is resolved. Many font managers will activate requested fonts from FCP X automatically, so disable your font manager’s auto-activation to help troubleshoot.


Font Corruption is rare but can really cause problems with Titles.

Symptom #10 Library won’t open. Warning that Library changes are unable to save. Very slow performance.

Diagnosis: Disk catalog or drive corruption (somewhat rare)

PrescriptionAt the minimum run First Aid using Disk Utility (found in /Applications/Utilities/Disk Utility). Unfortunately Disk Utility can’t correct all catalog issues and you’ll need something more powerful. Disk Warrior from Alsoft is the Mac industry standard. If you rely professionally on a Mac you should have a copy available.  

Storage problems in general can cause this error. Improper permissions, or other drive or network problem could be the culprit. Try copying your Library to a fresh drive to help you track down the storage problem.


Disk Utility and Disk Warrior are what I recommend to keep your drives healthy.

As sure as weeds will grown in your lawn, drive catalog problems will crop up. It’s a good idea to run Disk Utility and Disk Warrior on a regular schedule, or your main drives and your backup drives — the first of each month is a great place to start.

Symptom #11: A feature in FCP X doesn’t work, and nothing else helps.

Diagnosis: Corrupted user account or OS or FCP X app (rare)

PrescriptionCreate a fresh user account (System Preferences > Users) and see if problem persists in fresh user account. If the issue still persists try it on another Mac if you have it (or visit your local Apple store and use a Mac there). If it is resolved on another Mac it could be your FCP X is itself corrupted. Then delete your app and reinstall from the Mac App Store.

Can’t find your issue? See the next article in this series, 5 ways to make Final Cut Pro X faster, for more symptoms and solutions.

  • Alex Gollner

    Thanks for this T! I’m sure it will help many people.

    • T. Payton

      Thanks of the kind words Alex!

  • Nathan Slabaugh

    Great insights! (and a good reminder to run Disk Warrior more often) Thanks T.

  • Great Tips on FCPx troubleshooting

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  • FCP X 10.3.2. Crashes as soon as I click the “import button”. Nothing helps 🙁

    • T. Payton

      Sorry I missed being notified of this comment. Did you get it figured out?

      • Temporarily, yes. Not ideal, but it works.

        • T. Payton

          What was your temporary fix? Did 10.3.3 fix the issue? I assume you trashed preferences (#2) and tried a fresh user login to test (#11)?

  • Iain Davidson

    Thank you, great tips – especially RTFM 🙂

    • T. Payton

      Glad to do it!

  • Maria Tolly

    The video clip which I imported sometimes jerks. How can I stop this?

  • Pan Merak

    Hi, I have a problem when exporting. even if I use broadcast safe filter the export luma and pedestal go out of range

  • ELL

    Hi, I am editing a family members funeral video and it has disappeared from FCPX when I open. I found the library in my ext. hd but when I click I get: “This operation can’t be completed because an unexpected error occurred (error code -8058) I appreciate all help.

    • ELL

      Hi there is anyone able to help me?

  • David Demo Taliján

    Guys, help, please. What if I’m just creating a video. Effects (like blur on the screen or black/white mask) and titles are regulary visible. But then they just disappear and they aren’t showing up anymore when I try to put them on. It’s driving me insane. Thank you!

  • Rusty Earl

    Thank you T. for spending so much time on these articles. You have really helped my rethink the way I edit and have saved my bacon more than once with these troubleshooting guidelines.

  • frank

    For Me The Stock Plugins Crash Final Cut Pro X 3.4 Whats yup with that”?

  • Evert Sevenhuijsen

    The ‘flow’ transition in fcpx is magic, but is denied when exporting to Compressor. Is this a bug or my fault?

  • Loyalty Filmz

    my fcpx crashed and only some clips and images reappeared. but when i go to movies i can still see my original media. how can i get the rest of my project back into my timeline how i edited

  • Simon W.

    Thank you so much for this article. I have a serious problem with Final Cut X when it comes to rendering two or more stacked video tracks: In nearly all of my projects I will get some random Flash-Frames here and there (the video track beneath the one we see is visible for the lenght of 1 Frame). The only solution then is to delete the track beneath but now I have a picture in picture effect and FCPX keeps creating this render bug. I work in a ProRes422, 25p Event with. Any idea?

  • Fantastic post as well as great guidance! This article is very useful and helpful for us. Thanks for spreading valuable info.

  • Antoin Martin

    I am getting the word (null) next to my timeline, and my projects are not saving, any help?

    • Antoin Martin

      The video is on the timeline but it is greyed out, no titles are present although they show up in the video

  • Rebecca

    This is great! I have a different problem though. Every time I try to import my audio on the timeline, it speeds up my audio. I cannot get it back to the normal audio, which is very annoying. Do you know what the problem could be?

    • Buki Main Long

      Hi Rebecca! I’m sure you may have figured this out already and this is just a shot in the dark, but it sounds like the sample rate could be your culprit. Check to make sure that the audio file you are importing into your project has the same sample rate that your project does. I’ve experienced something similar when I try to import a 44.1 kHz file into a 48 kHz project (but this isn’t always the issue). You can see the properties of a file selected in your library by looking at the inspector within FCP. If the file doesn’t match your projects’ settings, you can always re-render the file with the proper sample rate and try again. I hope this helps! Have a great day!

  • Suzi Blu

    When I import video into FCPX a few parts of the clip look damage. If I click on ‘Reveal in Finder” and play the same clip in Quicktime, there is no damage. I am so confused. I appreciate any help.

  • Ray Mikota

    I am experiencing slight color changes in the video at the beginning and ends of one particular clip. end of first title fade up and through and the end of that clip . looks fine on the clips view, i tried replacing and re rendering im rendering in apple pro res 422? and then flickering at .17 sec in.

  • Ray Mikota .19 seconds in…? flickering… not in footage

  • Bang Em

    Hello, my fcpx closes it self out when trying to export master file or it will say invalid file when trying to export to youtube. Have you ever seen this before?