Will setting Offline and sync to No break anything for my users?

No. While online — which is how 99% of list usage happens — the list behaves identically. Views, forms, flows, Power Apps, search and APIs are unaffected. The only loss is disconnected access.

Does turning it off stop people downloading or exporting the data?

No, and this is important. It is a sync-limiting convenience control, not a security control. Users can still export to Excel, copy values, use the API, or screenshot. For real protection, use Conditional Access session policies and Microsoft Purview DLP.

Is "Yes" the default?

Yes. Every new SharePoint list and library allows offline availability unless you (or a site-level setting, or a provisioning template) change it.

Where is this setting for document libraries?

Same place — Library Settings → More library settings → Advanced settings → Offline and sync . For libraries, the newer UI splits it into two questions: syncing via OneDrive , and browser access without an internet connection . Both map to the same underlying ExcludeFromOfflineClient flag.

Can I disable it for the whole tenant at once?

There is no documented tenant-wide toggle for this specific property. The documented scopes are site collection (Site Settings → Search → Search and offline availability) and per list/library (Advanced settings). For tenant-wide control of the OneDrive sync client itself, use the separate OneDrive admin sync restrictions (device and domain based) — a different mechanism entirely. For everything else, script it with the PnP/CLI.

I changed the setting but it's still slow. What now?

Clear the browser's site data for your tenant (see Test 2 in the 5-minute test above). The old local mirror survives the server-side setting change until you remove it. If it's still slow after that, and it's slow in Incognito too, work through the server-side causes above.

How long does the change take to apply?

Server-side, immediately. Clients already holding a cached copy may need a sync cycle or a cache clear before they reflect it.

Does this affect Microsoft Lists on mobile?

The standalone Microsoft Lists mobile apps have been retired . Current list access on mobile is via the Lists web app and Teams, which are governed by the browser-offline half of this setting.

Do Power Apps offline features depend on this setting?

No. Power Apps canvas apps manage their own local cache (SaveData/LoadData) independently of the SharePoint list's ExcludeFromOfflineClient flag. Same for Microsoft Access's "work offline" linked tables — a separate mechanism.

SharePoint Offline and Sync: On vs Off Impact + Slow List Fix

If you have ever opened List Settings → Advanced Settings in SharePoint Online and stared at this question —

“Allow people to sync this list to their computers with Microsoft Lists and access it in the browser without an internet connection?” Yes / No

— and wondered which answer is “correct,” this guide is for you.

I’ll cover exactly what this setting controls, what changes when it’s On (Yes) versus Off (No), how to change it in the UI and with code, and then the question that brings most people here: why does adding an item to the list feel painfully slow in your normal browser, but fast in an InPrivate / Incognito window?

Honesty note up front: Microsoft documents what this setting does, but Microsoft has not published anything linking this setting to slow item creation. I’ll clearly separate documented facts from field experience and reasoned diagnosis throughout. Anyone who tells you “just turn Offline and Sync off and your list gets fast” is guessing. Below is the actual diagnostic path.

SharePoint Online list Advanced Settings — "Offline and sync" section with Yes/No radio buttons controlling Microsoft Lists sync and browser offline access. — *Specify whether this list can be accessed offline and synced to a computer.*

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