How to resolve an unexpected export problem in Final Cut Pro?

Error -12911 corresponds to an error from the macOS VideoToolbox framework kVTVideoDecoderMalfunctionErr.

The failure isn't in encoding your export but in decoding an existing render file. The path points into .fcpcache/.../Render Files/High Quality Media/, which is FCP's pre-rendered ProRes 422 cache stored in-library.

You can try deleting all render files by selecting the library in the left sidebar, then doing File > Delete Generated Library Files > Delete Render Files > All, then try the export again.

Also verify you have plenty of extra disk space on all drives. Since this happens on a large export, that could imply the space required for the output file or intermediate render files is inadequate.

My old memo when I had such error:

"The operation could not be completed because an error occurred when creating frame [n] (error 10004): preparing frame. "[project]" cannot be rendered at 00:01:11;27.)."

You might get away with just deleting all render files, and turning off background render (FCP 12.3 no longer defaults to it). To delete render files (which you should do anyway to reclaim disk space): select the library in the browser sidebar, and do File > Delete Generated Library Files... make sure to check All Render Files.

In Preferences > General set Time Display to "Frames" or to the same format as in the error report. Then in the timeline navigate to frame [n] and see what is there (zoom in enough to see individual frames). Delete that frame (with arrow keys and b blade tool).

Cannot render error - Apple Community

Re: suddenly there's an export problem

From your screenshot:

It seems the content in Frame 114 can not be rendered.

Therefore the export (via share) cannot be completed.

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Re: How to resolve

Seems necessary to examine / update / replace / or remove, the content that holds things up. (Frame 114 : "Boatbuilding in Lincoln County" ?)

"/Volumes/G-DRIVE with

Thunderbolt/FCPX/Ebb & Flow

23+.fcpbundle/.fpcache/Boatbuilding in

Lincoln County/Render Files/High Quality Media/

50C5EA894D- F85401501BED73B5BA0726"

Super large stills, especially TIFF and such, can bog FCP down pretty quickly. I see this weekly.

I'm not sure ... seems that is just helping identify it it is the "Boatbuilding in Lincoln County" file at that file address that can't be rendered.

The file in question is "High Quality Media" so it may have a rather large file size.

The DPI setting of a still image file has no relevance in video. It’s only the total pixel count that matters in video..

The “DPI” setting just tells a printer (Ink Jet, Laser, Press, etc.) how many dots per inch to print on paper, that’s it.

Thank you kindly for your thoughtful reply, and for letting us know just how you first found the cause, and then how you finally solved the problem! Great work! Grateful this info. is now available to others who may come looking for answers to similar issues. Cheers :-)