Why Won't My HEIC File Open or Convert?

This message appears before any decoding is attempted, based on the file's extension and type rather than its contents. Three things cause it.

It is a JPG or PNG that already got converted once. If a photo has already been through a conversion — by this tool, by an app, by an email service's automatic fallback — it is no longer a HEIC file at all, whatever the filename suggests. Check the actual extension.

It is the Live Photo's video half. A Live Photo is two files sharing an identifier: a still HEIC and a short separate video, conventionally saved with a .mov extension. If you picked up the video half by mistake, it will never be accepted as a photo to convert, because it genuinely is not one — what a Live Photo actually consists of explains the two-file structure.

Someone renamed a different file to end in .heic. Changing an extension does not change what is inside a file. If a .heic file arrived from an unfamiliar source, confirm what it actually is before assuming the check is wrong.

This one has nothing to do with your photo. The decoder itself is loaded as a separate piece of code the moment you start a conversion, and this message means that load failed — before your file was even touched.

Causes, roughly in order of likelihood:

A flaky connection interrupted the load. The most common cause by far. Refresh the page and try again, which is exactly what the message itself suggests.

A browser extension or strict privacy setting blocked the script. Ad blockers and aggressive privacy extensions occasionally interfere with scripts they cannot categorise. Trying in a private/incognito window, where most extensions are disabled by default, is a fast way to check.

An unusually old or restricted browser. Rare, but worth ruling out by trying a current version of a mainstream browser if the problem persists after a refresh.

Because this failure happens before your file is read, it can never be a sign of a problem with the photo itself — retry, and if it keeps happening, the browser or connection is the thing to investigate, not the HEIC file.

When one specific file fails partway through a batch and shows its own error while the rest convert normally, the problem is that individual file, not the tool or your other photos.

The file is truncated. Pulling a card reader out mid-transfer, a sync interrupted partway, or a download that did not finish all leave a file with a plausible name and size that stops short of being complete. Re-copying it from the original source — the phone, the backup, the card — usually resolves it immediately.

The file is corrupted. Storage does occasionally fail, and it tends to damage a handful of files rather than every one at once — which is exactly the pattern of "most of the batch is fine, three photos are not." If the original is still on the device that took the photo, re-export from there rather than from a copy.

It genuinely is not a HEIC file, but slipped past the initial check. The file-type check that catches most mismatches also accepts anything with no declared type at all, which some transfer methods produce. A file that passes that first check can still fail once the decoder actually attempts to read it, and the resulting error will be specific to whatever the file really contains.

To tell truncation from genuine corruption: if you still have the original — on the phone, in a cloud backup, on the card — comparing checksums between the copy and the original settles it in one step. Matching hashes mean the copy is faithful and the problem is upstream in the source file itself; different hashes mean the copy is simply incomplete and re-copying will fix it.

If a file displays fine in Photos or another viewer but a specific converter refuses it, the file is not the problem — the specific decoding path is.

heic2any, the decoder this tool uses, handles the overwhelming majority of real-world HEIC files, but no single decoder implementation handles every edge case of a broad format specification identically. A file produced by an unusual camera app, or one carrying a container feature a particular decoder does not expect, can occasionally trip up one tool while opening normally in Apple's own software.

If this happens: try a second, independent conversion path, which uses the same underlying decoder library but is worth attempting as an alternative route regardless. If neither succeeds and the file plays correctly in Apple's own Photos app, exporting it again from there — as a fresh JPG, using Photos' own share options — sidesteps the specific file entirely rather than continuing to fight it.

Not actually a failure, though it looks like one at first glance. If every ordinary photo in a batch converts cleanly and only Live Photos come out looking incomplete — missing the motion you expected — nothing has gone wrong with the conversion.

A Live Photo's motion lives in a separate video file, never inside the still HEIC that gets converted. No HEIC-to-JPG tool, this one included, can produce motion from a file that never contained it. What is actually happening covers the distinction properly — the still frame you get is correct and complete; the motion was simply never part of what you asked it to convert.