Why Windows won’t open HEIC files (and how to fix it)

HEIC has been the iPhone’s default photo format since iOS 11. It stores the same image in about half the space of an equivalent JPG, and supports transparency, sequences and more than 8 bits per colour channel.

The problem is licensing: HEIC uses HEVC compression, which is patented. Windows therefore does not ship the decoder — Microsoft even charged for it in the store. It is a royalty issue, not a technical one.

1. Convert to JPG. The definitive fix and the only one that guarantees the photo opens anywhere.

2. Install the HEIF codec. Works for viewing, but depends on your Windows version and does not help when a system only accepts JPG uploads.

3. Change the iPhone setting. In Settings → Camera → Formats, choose “Most Compatible”. Fixes future photos, not the ones you already have.

In Settings → Photos → Transfer to Mac or PC, “Automatic” converts photos to JPG over cable, while “Keep Originals” sends raw HEIC. That is why some photos open and others don’t — it depends how each batch was transferred.

The Localside HEIC to JPG converter decodes images inside the browser, with no upload, and takes several files at once. If the results are then too large to attach, the image compressor handles the second step.