Troubleshoot a Slow or Frozen Preview
If the preview stage stutters, lags, or freezes, this covers the usual causes — heavy templates, large images, low memory, too many tabs — and how to fix each.
#Symptom
The center preview stage stutters, drops frames, plays back slowly, or freezes entirely. The animation may loop unevenly or stop responding when you switch templates.
#Likely Causes
- A heavy template with lots of moving elements is taxing your machine.
- A large uploaded image (logo or a template image field) is embedded as a big data URL and is slow to redraw.
- Your machine is low on memory, often from many other tabs or apps running.
- Hardware acceleration is off in the browser, so animation runs on the CPU.
- You're in a browser that renders the stage less efficiently than a Chromium browser.
#Quick Fix
Close other tabs and heavy apps, reload HeyMotion in Google Chrome (desktop), and press ↺ Replay. If you uploaded a large image, swap in a smaller version. That clears most slowdowns.
#Detailed Troubleshooting
Work through these and re-check the preview after each:
- Close other tabs and apps. The preview redraws continuously as it loops; freeing memory usually restores smooth playback.
- Reload the page. A fresh load clears any accumulated state that can bog down the loop.
- Shrink large images. If you uploaded a high-resolution logo or template image, replace it with a smaller file — big data URLs are the most common cause of a sluggish stage. See Supported File Formats.
- Turn on hardware acceleration. In your browser settings, enable hardware acceleration so animation uses the GPU, then restart the browser.
- Use a Chromium browser. Google Chrome (desktop), Edge, Brave, and Arc render the stage efficiently. See Browser Requirements.
- Switch to a lighter template to confirm whether one specific graphic is the bottleneck.
- Give it a moment after edits. Content fields update the preview after a short debounce; rapid typing can look like a stall while it catches up.
A choppy preview does not mean a choppy export. Export renders frame-by-frame at 30 on a virtual clock, so the exported MP4 (H.264 / AVC, VP9 fallback) is frame-perfect even when live preview struggles on your machine.
#Collecting Diagnostic Info
If you still need help, note:
- Your browser and version, and whether hardware acceleration is on.
- The template and dimension where it slows down.
- Whether you uploaded an image, and roughly its size.
- How many other tabs/apps were open.
#When to Contact Support
If the preview stays slow after reloading in a Chromium browser with hardware acceleration on and no large images, email support@heymotion.io with the details above and the template id.
#Related Articles
See Preview an Animation and Browser Requirements.