DaVinci Resolve — troubleshoot the 5 most common breakage modes

Overview

A diagnostic protocol for the five problems that account for ~90% of DaVinci Resolve support questions: dropped-frame playback, missing media, audio sync drift, render crashes, and render queue stalls. The principle: diagnose before you fix. Treat the red indicator as data, not a verdict.

When to use

Symptoms:

• Red GPU/playback indicator during playback
• Clips show a red diagonal slash (offline media)
• Audio drifts out of sync over time
• Resolve crashes mid-render or after a few minutes of rendering
• Render queue says "complete" but the output file is missing or 0 bytes
• "Why is X broken in Resolve" — any of these.

When NOT to use:

• Resolve will not launch at all — that is an install issue (see davinci-resolve-setup).
• You are getting a license error — contact Blackmagic support.
• The problem is creative ("I do not like how my edit looks") — not a troubleshooting problem.

Quick reference — the five diagnostic flows

Steps — diagnostic flow per problem

Problem 1: Red playback indicator (dropped frames)

The indicator at the top of the source/timeline viewers turns red when Resolve cannot sustain real-time playback.

Step 1.1 — Identify the bottleneck. Is it the drive or the GPU?

• Open DaVinci Resolve > Preferences > System > Memory and GPU. Check GPU usage during playback.
• If GPU is below 80% during playback, the bottleneck is the drive (read speed).
• If GPU is pinned at 100%, the bottleneck is the GPU (rare for talking-head content; common for 4K + heavy color grading).

Step 1.2 — If the drive is the bottleneck, run Blackmagic Disk Speed Test:

• Free app, install from Mac App Store (macOS) or Desktop Video installer (Windows).
• Point it at your media drive. Look at the "Will It Work?" table. Confirm green checkmarks for your codec at your resolution and frame rate.
• If the drive cannot sustain the required read speed, you have two options:
  1. Move media to a faster drive (NVMe SSD, Thunderbolt).
  2. Generate proxies (see step 1.3).

Editor's Guide p. 326 details Blackmagic Disk Speed Test usage.

Step 1.3 — Generate proxies if you cannot upgrade the drive.

• In the Media Pool, right-click your clips > Generate Proxy Media.
• Choose a proxy format: H.264 Half-Res 1080p is a good default for editing.
• Wait for proxies to generate.
• Switch the Proxy Handling menu at the top of the viewer to Prefer Proxies.
• Playback should now be green.

Step 1.4 — Before delivery, switch back to camera originals:

• Proxy Handling > Prefer Camera Originals. Resolve renders from the high-quality sources, not the proxies.

Editor's Guide pp. 324-337 covers the full proxy workflow including the Blackmagic Proxy Generator separate app.

The misconception this addresses: "Red indicator means my computer is too slow." Often it means the drive is too slow, not the GPU. Diagnose first.

Problem 2: Clips offline (red diagonal slash)

A red diagonal across a clip thumbnail in the Media Pool or timeline means Resolve cannot find the source file at the path it was indexed at.

Step 2.1 — Determine if it is one clip or all clips.

• If all clips in a bin are offline, the source folder has moved or the drive is unmounted.
• If one or two clips are offline, those specific files have been moved/renamed.

Step 2.2 — For all clips offline (typical case: project moved to a new machine):

• Right-click the affected bin > Change Source Folder.
• Browse to the actual current location of the media on this machine.
• Click Change. All clips in the bin re-link in one operation.

Editor's Guide p. 336 shows Clip Operations > Change Source Folder.

Step 2.3 — For individual offline clips:

• Right-click the clip > Relink Selected Clips.
• Browse to the file. Resolve relinks just that clip.

Step 2.4 — If the file genuinely no longer exists:

• Check your backup folder (davinci-resolve-setup covers the backup folder location).
• Or check ~/.Trash / Recycle Bin if you may have deleted it.
• If the file is truly gone, you may need to re-shoot or re-export from the source.

Problem 3: Audio drifts out of sync

The audio is in sync at the start but drifts over time (e.g. 1 second off after 10 minutes).

Step 3.1 — Confirm the source clip frame rate matches the timeline frame rate.

• Right-click the source clip in the Media Pool > Clip Attributes.
• Note the clip's Frame Rate.
• File > Project Settings > Master Settings > Timeline frame rate. Confirm it matches.
• If they differ (e.g. clip is 29.97 fps but timeline is 24 fps), Resolve will interpret the audio differently. This is the most common cause of drift.

Step 3.2 — Check audio sample rate.

• Clip Attributes > Sample Rate (typically 48000 Hz).
• Project Settings > Master Settings > Sample Rate. Match them.

Step 3.3 — If video and audio were recorded separately (dual-system audio), re-sync them.

• In the Media Pool, select the video and audio clips together.
• Right-click > Auto Sync Audio.
• Choose Based on Waveform (works without timecode) or Based on Timecode (faster if both have matching timecode).
• Resolve aligns the two clips into a single synced clip.

Editor's Guide pp. 267-277 covers the audio sync workflow.

Step 3.4 — For drift caused by drifting hardware clocks (e.g. external audio recorder vs camera):

• Use the Stretch parameter on the audio clip in the Inspector to slow/speed by tiny amounts (0.5% or less).
• Or split the audio into multiple sections and re-sync each section.

Problem 4: Resolve crashes during render

Step 4.1 — Check the Console for the actual error.

• Workspace > Console opens the Console panel.
• Look at the last messages before the crash. Common causes:
  • "Out of memory" — reduce render frame rate or close other apps
  • "GPU error" — disable hardware decoding (see 4.2)
  • "File system error" — disk full or drive disconnected

Step 4.2 — Disable hardware acceleration if you see GPU errors.

• Preferences > Decode Options > uncheck Decode H.264/H.265 using hardware acceleration.
• This is slower but more stable, especially on older or mixed-GPU systems.

Step 4.3 — Reduce render concurrency.

• Some Resolve crashes during render are caused by trying to use both GPUs (in a dual-GPU machine).
• Preferences > System > Memory and GPU > set GPU processing mode to CUDA or Metal explicitly (not Auto).
• Restart Resolve.

Step 4.4 — Free disk space.

• Renders need 2-3x the source file size as scratch during processing.
• Check that both your media drive and your output drive have at least 50 GB free.

Problem 5: Render queue stalls at 0%

A render shows "Render in Progress" but the file size on disk does not grow.

Step 5.1 — Check the output filename for invalid characters.

• macOS file systems do not allow : in filenames. Windows does not allow < > : " / \ | ? *.
• If your render preset has %timeline_name and your timeline name contains a colon or slash, the render will silently fail.
• Rename the timeline first, or change the Custom Export filename to use plain characters.

Step 5.2 — Confirm the output folder exists and is writable.

• Check the Location field in Render Settings. Browse to it manually in Finder/Explorer.
• If it does not exist, create it.
• If it exists but is owned by another user, change permissions or pick a different location.

Step 5.3 — Reduce the render frame range.

• If a specific clip is corrupted, the render hangs on that frame.
• In Render Settings, change Render from "Entire Timeline" to "In/Out Range" and set an Out point before the suspected bad frame.
• If that completes, walk forward by a few seconds at a time to find the problem frame.

Step 5.4 — Restart Resolve.

• If all the above fail, kill Resolve (Force Quit on macOS, Task Manager on Windows) and reopen the project. Render queue often stalls after a long session and a restart clears it.

Common mistakes

• Assuming red indicator = old computer -> often it is the drive, not the GPU. Diagnose with Blackmagic Disk Speed Test first. (This is the misconception this skill addresses head-on.)
• Re-importing offline clips instead of relinking -> you lose all your edits if you re-import. Always relink.
• Letting Resolve auto-select GPU in dual-GPU systems -> manually set it to CUDA or Metal explicitly. Auto can cause crashes.
• Naming timelines with colons or slashes -> renders silently fail. Stick to alphanumerics, underscores, dashes.

Verification

You succeeded if all of the following are true:

1. Playback indicator is green during a 30-second play-through of your timeline.
2. Every clip in your Media Pool has a thumbnail (not a red diagonal).
3. Audio waveform aligns with video action throughout the timeline (clap on the slate matches the slate visual; mouth movements match speech).
4. Render completes and the output file is the expected size and duration.
5. You can identify which of the 5 problems applied (or no problem applied) by name.

Transfer

Now try this when you encounter a new breakage mode — say, a Fusion comp that will not render correctly. Apply the same diagnostic protocol: (1) identify the symptom precisely, (2) check the Console for an actual error message, (3) reduce scope (render just that one Fusion comp segment) to isolate the cause, (4) test a fix on a copy before applying to the project. This problem-solving discipline scales beyond the five cases above.

Working reference

• docs/wiki/editors-guide.md#lesson-6--ai-workflows-pp-323-387 (Disk Speed Test, proxies, relink workflows — primary)
• docs/wiki/editors-guide.md#lesson-5--project-organization-pp-245-321 (audio sync, frame-rate matching)
• docs/wiki/colorist-guide.md#lesson-8--adjusting-image-properties-pp-343-379 (Render Cache for Color-page playback)
• docs/wiki/master.md#reset-matrix--when-the-user-pushes-back-read-this (every troubleshooting symptom row maps here)

When the agent's work isn't matching expectations (context-rot reset)

If the user reports the diagnostic flow didn't fix the symptom (red playback returns, clips still offline, render still fails), read these PDF page ranges to reset:

• DaVinci-Resolve-20-Editors-Guide.pdf p. 326 (Is Your Drive Fast Enough? — Blackmagic Disk Speed Test)
• DaVinci-Resolve-20-Editors-Guide.pdf pp. 324-340 (Generating Proxy Files — complete workflow including Blackmagic Proxy Generator)
• DaVinci-Resolve-20-Editors-Guide.pdf p. 336 (Change Source Folder for bulk relink)
• DaVinci-Resolve-20-Editors-Guide.pdf pp. 267-277 (Syncing Audio to Video and Channel Configuration)
• DaVinci-Resolve-20-Editors-Guide.pdf pp. 597-617 (Customizing Deliver Presets, render failure causes)
• DaVinci-Resolve-20_Beginners-Guide.pdf pp. 6-8 (Relinking the Media Files)
• DaVinci-Resolve-20_Beginners-Guide.pdf pp. 350-364 (Syncing Audio to Video)
• DaVinci-Resolve-20-Colorist-Guide.pdf pp. 369-377 (Optimizing Performance with Render Cache — for color page playback)