--- title: "mobileassetd: what it is, why it downloads gigabytes, and whether to block it · Kilobat" url: "https://kilobat.app/processes/mobileassetd" description: "mobileassetd downloads system assets such as Apple Intelligence models on a Mac. What Apple documents, what is normal, and what breaks if you block it." --- Updates and downloads # What is mobileassetd? `mobileassetd` downloads system assets for macOS. Apple publishes no man page for it. Kilobat sees it, and its helper, download models, voices, fonts and dictionaries. Process: `mobileassetd` · Also seen as: `com.apple.MobileAsset.DownloadService.Builtin` · Made by Apple · Applies to: macOS 14 Sonoma and later. Apple Intelligence downloads need macOS 15.1 or later on a supported Mac. Checked on macOS 27.2. · Checked: 1 November 2026 ## Short answer Part of macOS, not documented by Apple. Kilobat sees it download system assets such as Apple Intelligence models, voices, fonts and dictionaries. Block with care Blocking it stops downloads of models, voices and other assets that macOS features need. To stop the biggest download, turn off Apple Intelligence. Path `/usr/libexec/mobileassetd` launchd label `com.apple.mobileassetd` Signing identifier `com.apple.mobileassetd` `com.apple.MobileAsset.DownloadService.Builtin` ## What it is Apple publishes no man page or documentation for `mobileassetd`. The program is `/usr/libexec/mobileassetd`, signed by Apple. launchd starts it as `com.apple.mobileassetd`. A helper named `com.apple.MobileAsset.DownloadService.Builtin` does downloads for it. In `nettop`, its name is cut to 15 characters. Kilobat's list of system downloads says that it gets Apple Intelligence and Siri models, voices, fonts and dictionaries. This is what Kilobat observes, not what Apple documents. ## Why it uses the network - **Apple Intelligence models.** Apple says that the on-device models download after you turn on Apple Intelligence, and that the download time varies. - **Voices, fonts and dictionaries.** Kilobat's list of system downloads names these assets too. Apple doesn't document when they download. - **New models after an update.** Apple says that Apple Intelligence storage can grow for a time after a software update, while new models download. ## How much is normal Downloads after a macOS update, or after you turn on a feature, are usual. Apple Intelligence models can be several gigabytes. Apple recommends Wi-Fi and power for the Apple Intelligence download. When nothing new is needed, it is quiet for days. ## When it uses a lot, and why - **You turn on Apple Intelligence.** The on-device models download. This is the largest download it makes. - **Right after a macOS update.** Apple says that new models can download for a time after a software update. - **A new voice or language.** Adding a voice, a dictation language or a dictionary downloads that asset. Kilobat sees these under this service. ## Is it safe to block? Block with care Blocking it stops downloads of models, voices and other assets that macOS features need. To stop the biggest download, turn off Apple Intelligence. What breaks if you block it - Apple Intelligence can't finish setting up, and new models after an update don't arrive. - New voices, languages and dictionaries can't download. - Apple doesn't document every asset it handles, so other features that need a download may fail too. Blocking means a firewall rule that refuses its connections. Don’t quit or disable a macOS process to save data: macOS starts it again, and other features depend on it. ## Reduce its use 1. Do macOS updates on your usual network. The asset downloads follow them. 2. If you don't use Apple Intelligence, turn it off in System Settings › Apple Intelligence & Siri. Apple says that the on-device models are then removed. 3. Add voices and languages only when you are on your usual network. 4. Don't quit `mobileassetd` in Activity Monitor. macOS starts it again. ## See how much it uses 1. Open Activity Monitor from Applications › Utilities. Click Network. 2. Type `mobileassetd` in the search field. The Sent Bytes and Rcvd Bytes columns show what it moved since it started. 3. In Terminal, watch only this process. Press d to show the change per second, and q to quit. ``` nettop -p 'mobileassetd' -P ``` ## With Kilobat 1. In the Kilobat app list, search for `mobileassetd`. Its row shows the live rate and what it moved today. 2. In Connections, click the ⓘ button on one of its rows. The popover shows this page’s short answer, without going online. 3. In Terminal, ask the same question. Add `--json` for scripts and agents. ``` kilobat explain 'mobileassetd' ``` 4. Show its traffic over one day. ``` kilobat bandwidth 'mobileassetd' day ``` 5. Through MCP, an AI agent asks `explain_connection` with the process name. It gets the same facts. The live view and the explanations are free. History in the app needs Kilobat Pro. Blocking needs Pro and the network filter: see the [network filter](https://kilobat.app/docs/blocking#filtering), [Protection](https://kilobat.app/docs/blocking#protection) and the [hotspot data saver](https://kilobat.app/save-hotspot-data). ## What isn’t documented Apple publishes no man page and no support article for `mobileassetd`. Which assets it downloads, and when, is not documented. This page describes what Kilobat and the macOS tools show, and what Apple says about Apple Intelligence downloads. ## Questions **Why does Apple not document mobileassetd?** Apple publishes man pages for some daemons only. This page describes what Kilobat and the macOS tools show. **Can I stop Apple Intelligence downloads?** Turn Apple Intelligence off. Apple says that the on-device models are then removed from the Mac. ## Sources - launchd property list com.apple.mobileassetd, macOS 27.2 - [Apple Support: Get started with the next generation of Apple Intelligence](https://support.apple.com/en-us/121115) - [Apple Support: Apple Intelligence and privacy on Mac](https://support.apple.com/guide/mac-help/apple-intelligence-and-privacy-mchlfc0d4779/mac) - [Apple Support: View network activity in Activity Monitor on Mac](https://support.apple.com/guide/activity-monitor/view-network-activity-actmntr1006/mac) - [Kilobat docs: System downloads](https://kilobat.app/docs/usage#system-downloads) Checked on 1 November 2026. ## Related - [softwareupdated](https://kilobat.app/processes/softwareupdated): Part of macOS. It checks for and downloads macOS updates, security responses and system files. - [privatecloudcomputed](https://kilobat.app/processes/privatecloudcomputed): Part of macOS. It encrypts and sends Apple Intelligence requests that need a larger model to Apple's Private Cloud Compute servers. - [nsurlsessiond](https://kilobat.app/processes/nsurlsessiond): Part of macOS. It does background downloads and uploads that apps hand to macOS, so its traffic belongs to those apps. - [Mac uses Personal Hotspot data in the background](https://kilobat.app/guides/hotspot-background-data)