Why won’t my video compress on iPhone? Fixes for stuck or failed compression

With iCloud Photos on and Optimize iPhone Storage selected, the phone can keep a small preview and leave the full-quality video in iCloud. A compressor or editor needs the full file, so it has to download it first. If you are offline, on a weak connection or iCloud is full, that download stalls and the job looks stuck or fails.

Open the video in Photos. If it shows a progress circle or loads slowly, it is not fully on the phone. Stay on Wi-Fi and wait for it to finish, then try again. To keep full-quality copies on the phone, open the Photos settings (Settings, Photos, or under Apps on newer iOS versions) and choose Download and Keep Originals, as long as there is room for them.

Compressing writes a new file next to the original, so the phone needs room for both until you delete one. Check Settings, General, iPhone Storage. A few hundred megabytes of free space is rarely enough for a long 4K clip, and an export can fail partway when space runs out.

Two quick ways to get space back: empty the Recently Deleted album in Photos, because deleted videos keep using space there for about 30 days, and delete apps or downloads you no longer need. For a bigger clean-up, see the guide on freeing up storage without deleting videos.

Encoding a video is heavy work and iOS limits what an app may do once you leave it. If you switch apps or let the screen lock, many compressors pause or stop, and the job may restart from the beginning or fail. Keep the app open and the screen on until it finishes. Turning on Low Power Mode can also slow things down, so switch it off for a long clip.

A long 4K video can take several minutes on an older iPhone. A clip that is clearly moving, with a progress bar or time estimate, is not stuck.

Long 4K at 60 fps, slow-motion and Dolby Vision clips are the heaviest. If a very big file fails, trim it first so each piece is shorter, or compress it at a lower resolution. Videos from other apps or cameras in unusual formats may not open at all on iOS; in that case, play one in Photos or Files first to see whether the phone can read it.

If the video was edited, exported or saved from another app, also see why a compressed video can end up bigger than the original.

Minivid compresses on the iPhone with its hardware encoder, and the original is never modified. If a compression stops before it finishes, nothing is saved and the original stays untouched; its message suggests trying again, and a smaller preset if that does not help. While it runs, the screen asks you to keep Minivid open, and you can cancel at any time.

If it cannot read a file, it says so and notes that the video may still be downloading from iCloud or be in a format the phone cannot play. A video that exists only in iCloud is downloaded before it is compressed. If saving fails, the app asks for permission to save to Photos, which you can allow in Settings.

1. 1Open Minivid and choose the video. If it is in iCloud, let it finish downloading.
2. 2Check the Estimated size on the settings screen, and use Trim first if you only need part of the clip.
3. 3Tap Make it small and keep Minivid open on screen until it finishes.
4. 4If it stops, tap Try again, or tap Change settings and pick a smaller preset such as Save Space.

In the free version, Minivid handles videos up to 100 MB and writes the result at up to 720p. A bigger video, or a result above 720p, needs Pro. If a video is refused for size, that is the free limit and not a fault with the file.