---
title: "Share Across Devices not working: the fixes, in order · finit"
description: "When Screen Time won't sync across iPhone, iPad and Mac: the account check, the greyed-out toggle, the switch that turns itself off, and the disagreeing numbers, each with its fix."
url: https://getfinit.com/ja/blog/share-across-devices-not-working
lang: ja
published: 2026-06-16
modified: 2026-06-16
---

# Share Across Devices not working: the fixes, in the order to try them

2026年6月16日 · 3分で読めます · finitの開発チームより

Share Across Devices has exactly one job, one combined Screen Time total across your iPhone, iPad and Mac, and several quiet ways to fail at it: the toggle greyed out, the switch that turns itself back off, devices that just never agree. The causes are few and boring, which is good news. Here they are, in the order worth checking.

## First: the account check

The feature only merges devices signed into the **same Apple Account**. On every device, confirm the account at the top of Settings is identical, then confirm **Settings → Screen Time → Share Across Devices** is switched on, on each device separately; the toggle is per-device, and one forgotten iPad quietly breaks the merge. A device signed into a second account, a work account for instance, will never join.

## If the toggle is greyed out

A greyed toggle almost always means the account on this device isn't in a state that supports the merge: typically a child account managed through Family Sharing, where Screen Time is controlled by the family organizer instead, or a device under management (a school or work profile) that owns those settings. In the child case this is by design, and the parent's device is where the reporting lives. There is no hidden switch behind it.

## If it keeps turning itself off

The switch depends on the account's cloud session, so it falls over where that does. The sequence that clears most cases: turn the toggle off on all devices, restart them, sign out of the Apple Account on the misbehaving device and back in, then turn the toggle on everywhere again. It is tedious and it works, because it forces the session the sync rides on to be rebuilt. If it still won't hold, check for a pending Apple Account verification in Settings; an unverified session is a classic silent blocker.

## If the numbers just disagree

Sync is slow by design; minutes to hours of lag between devices is normal, and the current day is the least settled of all. Compare finished days before concluding the merge is broken, and remember what merging does to the totals: your Mac afternoon lands in the same headline number, which reads like inflation if you forgot the merge exists. [Wrong-looking totals have their own page](https://getfinit.com/ja/blog/screen-time-wrong), and a merge that rewrites history is [cause four on the disappeared list](https://getfinit.com/ja/blog/screen-time-disappeared).

## 短い答え

### Why is Share Across Devices greyed out?

Usually because the device is signed into a child account managed through Family Sharing, or is under a school or work management profile. In both cases the setting is controlled elsewhere by design, and there is no way to force it on from the device itself.

### Why does Share Across Devices keep turning off?

The switch rides on the Apple Account's cloud session. Turning it off everywhere, restarting, signing the affected device out and back in, and re-enabling the toggle on every device rebuilds that session and resolves most cases.

### Why don't my devices show the same Screen Time?

Syncing lags by minutes to hours, and today's numbers settle last. Make sure the toggle is on for every device under the same Apple Account, then judge by yesterday rather than by the live number.

### Does turning it on bring in past history?

No. The merge combines activity from the time it is enabled; it does not backfill weeks a device recorded alone, and nothing recovers weeks the rolling window has already deleted.

Once the merge finally holds, remember what it still can't do: remember. The combined record still [deletes itself after about four weeks](https://getfinit.com/ja/blog/screen-time-history), on every device at once. [finit is where the merged days go to survive](https://getfinit.com/ja/why).

[App Storeからダウンロード](https://apps.apple.com/us/app/finit-screen-time-life/id6786888937?pt=128650426&ct=web-agent&mt=8) [アプリで見る →](https://getfinit.com/ja/#app)

---

Markdown twin of https://getfinit.com/ja/blog/share-across-devices-not-working. Site map for agents: https://getfinit.com/llms.txt. Every English page in one file: https://getfinit.com/llms-full.txt.
The same page in another language: the same path with a language segment in front, https://getfinit.com/de/blog/share-across-devices-not-working.md for one; the list is in llms.txt.