Box 'Preview Didn't Load' Error
Workaround available Web Updated October 21, 2026
Quick answer
Box shows 'We're sorry, the preview didn't load' when the file's preview conversion fails or the browser blocks it. Try another browser and clear the cache. If only one file fails, re-upload it so Box converts it again.
Most likely fix: Try another browser and clear the cache.
Symptoms
A blank preview or the 'preview didn't load, please refresh the page' message for some files, often large Office files or PDFs, while other files in the same folder preview fine.
Why it happens
- Failed or stuck preview conversion on Box's side
- Unsupported file type for preview
- Browser cache, extensions or browser-specific bugs
- Firewall or security software blocking preview content
How to fix it
Try these in order — the most common fix is first.
1. Try another browser and clear the cache
- Update the browser and clear its cache
- Open the file in a different browser, computer or network
2. Disable extensions and security software temporarily
- Turn off ad blockers and other extensions, then reload
- If you're on a managed device, ask IT before disabling firewall or security tools
3. Re-upload the file
- Download the file and upload it again so Box reruns the conversion
- Box's guide says the file should then preview correctly
4. Download and open locally
- Use Download or Box Drive to open the file in its native app while the preview is broken
5. Send a network capture to support
- Open DevTools (F12) > Network, reproduce the error, and export a HAR file
- Open a ticket at support.box.com and attach the HAR
This guide also covers
- box preview didn't load
- box preview not loading
- we're sorry the preview didn't load box
- box file not previewing
- box pdf preview not working
Still not working?
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