Control OneDrive for Business syncing to prevent data copies on non-domain-joined PCs

One of the recently announced changes to Office 365 is the ability to better control OneDrive for Business. Specifically, it’s now possible to control OneDrive for Business syncing to prevent data from being copied to non-domain-joined PCs, based on a list of approved domains, as well as to change the storage limit for users (perhaps 1TB is just too much data and something more restrained might reduce the impact on your network). There are also some changes around the “Shared with Everyone” folder, which used to be created by default but isn’t anymore.

The full details are in an Office Mechanics video, linked from a Microsoft blog post but I recently had the chance to try them out for real.

Step 1 was to determine the ObjectGuid for each of the domains in my customer’s Active Directory Forest, using Active Directory PowerShell:

$domains = (Get-ADForest).Domains; foreach($d in $domains) {Get-ADDomain -identity $d | Select ObjectGuid}

Step 2 is to connect to Office 365 using PowerShell:

$cred=Get-Credential
connect-sposervice –url https://tenantname-admin.sharepoint.com/ –credential $cred

Step 3 is to take the ObjectGuid from step 1 and use the Set-SPOTenantSyncClientRestriction cmdlet to restrict synchronisation:

Set-SPOTenantSyncClientRestriction -enable -DomainGuids "a0083dbb-e136-4f48-a048-2ec3a4c40cab"

It’s worth noting that, initially, this failed for me – SetSPOTenantSyncClientRestriction wasn’t a valid command in the version of the SharePoint Online Management Shell I had installed. I checked the version with Get-Module -ListAvailable | Format-List version, name and found I had version 15.0.4569.0 of Microsoft.Online.SharePoint.PowerShell. After updating to the latest version, I was at version 16.0.4316.0, which worked a treat:

TenantRestrictionEnabled AllowedDomainList

———————— —————–

True {a0083dbb-e136-4f48-a048-2ec3a4c40cab}

It’s important to understand how the restrictions are enforced though:

  • Not only will OneDrive for Business Sync client requests originating from a domain that is not on the safe recipients list be blocked but all OneDrive for Business Mac Sync client requests will be blocked. This also means that a sync relationship will not be established unless they are joined to an allowed domain.
  • However:
    • Mobile clients are not blocked (there are separate MDM controls for this) and any files that have been previously been synced to the computer will not be deleted.
    • New or existing files added to the client will still be uploaded to the server and will not be blocked.
    • OneDrive for Business sync client prior to version 15.0.4693.1000 will stop syncing existing libraries.

Controlling the storage quota was a little more tricky. I found that I could use Get-SPOSite -Identity https://tenantname-my.sharepoint.com/personal/firstname_lastname_tenantname_onmicrosoft_com to view the properties of a users’ OneDrive for Business site, but attempting to set the quota on the same site presented an error:

Set-SPOSite -Identity https://tenantname-my.sharepoint.com/personal/firstname_lastname_tenantname_onmicrosoft_com -StorageQuota 2048

Set-SPOSite : Cannot get site https://tenantname-my.sharepoint.com/personal/firstname_lastname_tenantname_onmicrosoft_com.
At line:1 char:1
+ Set-SPOSite -Identity
https://tenantname-my.sharepoint.com/personal/firstname_lastname …
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [Set-SPOSite], ServerException
+ FullyQualifiedErrorId : Microsoft.SharePoint.Client.ServerException,Microsoft.Online.SharePoint.PowerShell.SetSite

I haven’t fixed that yet, so I’ll be returning to the topic again soon, no-doubt…

Post Script

There is a known issue with domain joined PCs failing to sync OneDrive for Business, even when added to a safe list, which is fixed by the 12 May 2015 update for OneDrive for Business (see Microsoft knowledge base article 2986244).

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