Slack's cloud sync is what lets your messages follow you from device to device. Here is exactly how it works, what it covers, and how to make sure it runs smoothly.
Slack keeps your account-level data — messages, channels, direct messages and workspace membership — in the cloud. When you sign in on any device, Slack downloads that data and keeps it current in real time, including which messages you have already read. Unlike apps where history can live only on one machine, Slack's model means your conversations are consistent everywhere by default. The local app keeps a cache for speed and offline access, but the authoritative copy is always in the cloud.
On each device, sign in with the same account to the same workspace. This is the foundation of sync — your account is the thing that roams.
If you belong to several workspaces, add them all on each device. Each workspace syncs separately, so they need to be signed in individually.
When signing in on a new device, approve any verification step Slack sends. This keeps your synced account secure.
Sync needs a working internet connection. If messages seem stale, confirm you are online — the desktop app shows recent cached content even while reconnecting.
If a device shows out-of-date messages, quit Slack and clear its local cache. It rebuilds from the cloud on next sign-in, which resolves most stale-sync issues.
Slack stores your messages, channels and workspaces in the cloud against your account. When you sign in on any device, Slack downloads that data and keeps it updated in real time, so every device shows the same conversations and read state.
Not really — cloud sync is automatic. You just sign in with the same account on each device. The main thing to get right is signing in to the correct workspace, since each workspace syncs separately.
The usual causes are being signed in to a different workspace or account, a poor network connection, or a stale local cache. Confirm the account and workspace, check your connection, and clear the cache with Slack closed if needed.
Sign in with one account and keep your messages everywhere.