You plug your iPhone into a Windows 11 laptop, drag a folder of vacation photos onto the desktop, double-click the first one — and either Windows Photos opens to a blank screen, or you get a dialog that says "HEIF Image Extensions is required to display this file." This is one of the most-Googled image problems of the last five years. The frustrating part is that there is not one cause; there are six, and the right fix depends on which one you are hitting.

HEIC (High Efficiency Image Container) was introduced by Apple in iOS 11 back in 2017 to cut iPhone photo file sizes roughly in half compared to JPG. Microsoft never bundled native HEIC support with Windows — it sat behind two separate extensions in the Microsoft Store, one of which costs money. Even today, on a fully updated Windows 11 24H2 install, double-clicking a HEIC file in File Explorer is still a coin flip. The next section walks through the six failure modes I see most often, with the actual fix for each.

(1) The HEIF Image Extensions are not installed. Windows ships with no HEIC decoder by default. Open Microsoft Store, search "HEIF Image Extensions", install it — free. (2) The HEVC Video Extensions are missing. HEIC actually uses the HEVC video codec under the hood. The OEM variant used to be free; the standalone one from Microsoft now costs $0.99. Without it, photos with newer HEIC variants fail silently. (3) You transferred via AirDrop or iCloud rather than USB. When the iPhone sends photos to a non-Apple device over USB it can auto-convert to JPG on the fly, but AirDrop and an iCloud download give you the original HEIC. Go to iPhone Settings → Photos → Transfer to Mac or PC → set to Automatic instead of Keep Originals.

(4) The file extension is .heif rather than .heic. These are the same format — Apple writes .heic, other devices and some cloud services rewrite to .heif. Windows registers extensions separately, so a .heif file can fail to open even when .heic works. Rename the extension and try again. (5) The file is actually a Live Photo (HEIC + MOV pair). What looks like a single tap-to-view in iOS Photos is two files on disk. The MOV half cannot open in Windows Photos either; you only need the HEIC half as a still image. (6) The HEIC file is from a third-party iPhone camera app (Halide, ProCamera) using an HDR / 10-bit variant. Microsoft's extension does not handle every HEIC profile — specifically the newer Adobe RGB / Display P3 HDR variants — and silently shows a black or fully-white preview.

If you have already installed both Microsoft extensions, reinstalled them, restarted Windows, and the files still won't open — convert them to JPG. JPG is universally supported by every Windows app from the last 30 years (File Explorer thumbnail, Photos, Word, Outlook attachments, every browser). The conversion is also visually lossless in practice — the HEIC was already compressed once, the JPG re-encodes the decoded pixels, and at quality 90+ the visual difference is invisible. The downside is the JPG is roughly twice the file size of the HEIC, but that only matters if you are storing thousands of photos.

You can convert HEIC to JPG without uploading anything by using PCToolsOnline directly in your browser — drag the folder onto the page, every file is decoded locally via a WebAssembly build of libheif, and the JPGs are downloaded back to your machine. No iCloud, no third-party site sees the photos, no codec to install. For a single photo this takes about 3 seconds; for a batch of 50 vacation photos, about 2 minutes total. If most of your iPhone photos end up on Windows anyway, change the iPhone setting (Settings → Camera → Formats → Most Compatible) so future shots are saved directly as JPG and you skip this whole problem at the source.