How to Fix Common HEIC Conversion Errors

Confirm the source file

• Open the original on the device that created it.
• Check that the file finished copying and is not zero bytes.
• Confirm the extension is .heic or .heif.
• Download cloud-only originals before attempting local conversion.
• Do not rename .heic to .jpg; that changes the label, not the encoded data.

Reduce browser memory pressure

High-resolution HEIC decoding can temporarily use much more memory than the compressed file size suggests. Close memory-heavy tabs, convert fewer images at once, and retry the largest photos individually.

If one file repeatedly fails while others convert, it may use a HEIF feature the browser decoder does not support or it may contain multiple image items. Try exporting a compatible copy from Photos or Preview on the originating Apple device.

Check the result before retrying

If conversion appears to finish but the result does not open, download it again and verify that security software or a browser extension did not block the generated file. A private window with extensions disabled can help isolate interference.