Understand disk space and compression

Why Hindsight uses disk space

Hindsight builds a searchable local timeline from the things it captures on your Mac. That timeline needs disk space because Hindsight is not only saving text. It also keeps enough visual history to let you open a result and understand what was on screen at that moment.

The exact amount of storage is different for every Mac. It depends on display resolution, how often your screen changes, how many hours Hindsight records, whether audio transcription is enabled, and how long you keep local history.

Hindsight’s Storage settings show Current Disk Space Used for local history. That number includes the local timeline data Hindsight manages, not every byte on your Mac that might be related to the app. The app itself takes a little space too.

What Hindsight stores locally

Hindsight stores local history in a private storage area inside the app’s Application Support folder. At a high level it keeps a few kinds of data:

• A local database with timeline metadata, OCR text, search indexes, a small preview of each screen, and audio transcript records.
• Encrypted, compressed video recordings that preserve the visual timeline more efficiently than keeping every screenshot as a standalone image.
• Encrypted pictures of their own for the screens you star, so they outlive the recording they came from.
• The transcription model, which Hindsight downloads during setup.

The database, the recordings and the pictures are all encrypted at rest. This protects stored history on disk, but it does not make the files free. Encrypted data still occupies normal disk space.

Why storage usage is not a simple minutes-to-gigabytes number

Two people can run Hindsight for the same amount of time and see different storage usage. The largest factors are content, resolution, and retention.

A mostly static screen compresses well. A screen with video playback, animations, screen sharing, design work, or constant motion uses more space because each captured moment contains more visual change. Larger displays can also use more space because there are more pixels to represent, even though Hindsight caps stored visual dimensions before writing thumbnails and video frames.

Hindsight also skips duplicate visual frames. If the screen has not meaningfully changed, Hindsight does not need to save the same moment again. This is why an idle workday can use much less space than a day full of meetings, video, dashboards, and browser tabs changing every few seconds.

How often Hindsight captures

Hindsight checks the screen periodically in the background. A check does not always become a stored frame. Hindsight compares each new screenshot with the previous captured frame, and if the screen has not meaningfully changed, the moment is treated as a duplicate and skipped.

That means storage is affected by both time and activity:

• More active screen changes usually create more saved frames.
• Repeated or still screens usually create fewer saved frames.
• Recording for more hours creates more opportunities for frames.
• A shorter retention period removes old frames sooner, apart from screens you star.

This is also why storage can grow quickly during visually busy work, then grow more slowly while you read or leave the same window open.

How previews are stored

For each saved screen, Hindsight keeps a small preview for the timeline strip. Previews are downscaled and encrypted, and they live in the local database rather than as files of their own.

Previews let the timeline show a long run of screens quickly without opening a recording for each one. They also make search results feel responsive.

Previews are only a small part of local history. If you see disk usage grow, it is mostly the recordings, with metadata, previews and audio transcripts making up the rest.

How compressed recordings work

Hindsight does not keep every captured screenshot as an individual full-size image. Instead, it records your screens into short videos, each holding up to 150 screens.

Each screen goes to the video encoder built into your Mac the moment it is captured. The encoder compresses it, and Hindsight encrypts it and adds it to the open recording before the next screen comes along. Nothing is written to disk unencrypted and there are no temporary working files, so disk usage grows steadily rather than in bursts.

The encoder is tuned for local history rather than for archival recording. The goal is small files with text that stays readable, so it favors compact size over pristine video quality. That is intentionally different from a movie export: Hindsight’s goal is not cinematic quality, but a readable, searchable visual memory that uses far less disk space than raw screenshots.

There is nothing to install for any of this. The video encoder is part of macOS, and on a Mac with Apple silicon it runs in dedicated hardware, which keeps compression light on battery and processor time.

How audio search affects storage

Audio search has two storage parts.

First, Hindsight downloads a local transcription model. It runs on your Mac, downloads once, and uses about 630 MB. If you downloaded models in an earlier version of Hindsight, they’re deleted once the current model is ready.

Second, Hindsight stores transcript records so audio can appear in search. The transcript text is much smaller than visual history, but it still contributes to the local database and search index.

The model stays on your Mac, since audio and meetings can’t be transcribed without it. It isn’t part of local history, so retention never removes it.

How retention controls disk usage

Retention is the main long-term control for local history size. Hindsight can keep history for 1 month, 3 months, 6 months, 1 year, or forever. The default is 3 months.

When you reduce retention, Hindsight removes frames and audio older than the selected cutoff. It also purges deleted frame data and removes a recording once no screen left in your history is in it.

Screens you star are the one exception. A star means you want that screen kept, so retention never takes it, and the audio recorded while it was on screen stays with it. A starred screen is removed only when you delete it, when you delete all local data, or when you remove its star and it falls outside the retention period.

Reducing retention saves disk space, but it also limits how far back you can search. Choose the shortest period that still matches how you use Hindsight.

Why disk usage can stay high after changing retention

After retention changes, Hindsight deletes old data, previews, audio, and recordings no longer needed. A recording holds up to 150 screens, and if one of them is still inside your retention window, Hindsight keeps the whole recording for it. A starred screen keeps a picture of its own, so it never holds a recording back.

This is normal. Storage may drop in steps rather than perfectly matching the new retention period immediately. It can also take a moment for the storage number to refresh.

If usage still looks unexpectedly high, open Settings again and check the displayed local history size after Hindsight has had a chance to apply retention.

What to do when disk usage looks too high

Start with the controls inside Hindsight rather than deleting files in Finder.

1. Open Hindsight Settings.
2. Go to Storage.
3. Check Current Disk Space Used.
4. Reduce the retention period if you do not need older history.
5. Keep Hindsight open long enough for retention cleanup to run.
6. Review excluded apps if specific apps create noisy or unnecessary history.
7. Consider disabling recording on battery if you do not want Hindsight capturing during mobile use.

If a particular workflow uses a lot of space, it is usually because the screen changes frequently. Video calls, video playback, live dashboards, design canvases, development tools with constant output, and screen recordings all create more unique frames.

What not to delete manually

Avoid manually deleting Hindsight’s local storage files while the app is running. The database, recordings, and pictures reference each other. Removing only one part can leave the database pointing at missing files, or leave files that the app can no longer account for cleanly.

Use Hindsight’s Storage settings when you want to reduce local history. If you need to remove all local app data for troubleshooting, quit Hindsight first and make sure you understand that this removes searchable history from the Mac.

How to think about compression quality

The recordings are meant for recall, not archival video. Hindsight compresses frames aggressively because the important job is to recover context: which app was open, what text appeared, what page you were on, and what was happening around a search result.

Text, app layout, and broad visual context should remain useful. Fine details can be softer than the original screen because Hindsight scales stored frames and uses high-compression video settings. That tradeoff is what keeps a long-running local timeline practical.

When to contact support

Contact support if Hindsight shows a compression error or storage keeps growing even after you shorten retention and let cleanup run.

Include these details:

• Your macOS version.
• Your Hindsight version.
• The retention period selected in Settings.
• The local history size shown in Storage settings.
• Whether audio search is enabled and the transcription model is downloaded.
• Whether the issue started after an update, reinstall, migration, or crash.
• The exact error message if Hindsight shows one.

Those details make it much easier to separate normal local history growth from a compression, retention, or installation problem.