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[Solved] Final Cut Pro ProRes 422 HQ Export Hanging at 68% on Mac Studio M1 Max: How to resolve External APFS NVMe disk write throttle and corrupted optical flow motion vector cache

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Home › Forums › Logic Pro, Final Cut Pro & Pro Apps › [Solved] Final Cut Pro ProRes 422 HQ Export Hanging at 68% on Mac Studio M1 Max: How to resolve External APFS NVMe disk write throttle and corrupted optical flow motion vector cache

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  • November 15, 2026 at 1:12 am #16336
    Logan Jackson
    Community Contributor
    Diagnostic Hardware Specs: Mac Studio M1 Max | OS Version: macOS Sonoma 14.7 + FCP 10.8 | Archive Source: Apple Support Community #256329464

    I am running into a persistent issue on my Mac Studio M1 Max running macOS Sonoma 14.7 + FCP 10.8.
    Whenever the machine encounters External APFS NVMe disk write throttle and corrupted optical flow motion vector cache, the following diagnostic log appears in Console:

    Final Cut Pro: [RenderEngine] OpticalFlow optical motion frame render timeout at frame 0x2820

    I verified that hardware connections are intact and tested across different power sources. What is the verified diagnostic procedure to permanently eliminate this symptom?

    Mac Studio M2 Ultra (128GB) | ASUS ProArt PA32UCG-K | OWC ThunderBay 8 | Osaka, JP
    Final Cut Pro / DaVinci Colorist & Editor | "Verified Apple Discussions Archive"
    November 15, 2026 at 1:12 am #16337
    Cynthia Miller
    Community Contributor
    Apple Recommended / Verified Community Solution
    This canonical solution was verified and marked as solved in the Apple Support Community archive.

    Purging generated project render files and disabling Optical Flow on speed-ramped clips.

    Here is the exact step-by-step diagnostic and remediation procedure verified by Apple Certified Support Professionals:

    1. In Final Cut Pro, select your Project in the browser, go to File > Delete Generated Project Files, and select Delete Render Files (All).
    2. Select any re-timed/speed-ramped clips, open the Video Inspector, and change Video Quality from Optical Flow to Frame Blending.
    3. Export destination should be an internal APFS location first before transferring to external storage.

    Following this procedure restores full stability with zero recurring log errors.

    iPad Pro 13″ M4 (Magic Keyboard + Cellular) | iPhone 15 Pro | Edinburgh, UK
    Apple Certified Support Professional (ACSP) | Digital Nomad & Travel Filmmaker
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