Prevent users from syncing libraries and folders shared from other organizations
Verified with Microsoft OneDrive 26.153.0809.0004 — updated on July 10, 2026
Supported on: At least Windows Server 2008 R2 or Windows 7
Path in the GPO console
Computer Configuration\Administrative Templates\OneDrive Description
This setting controls whether users in your organization are allowed to sync OneDrive for Business or SharePoint content that has been shared by users in a different organization. This is a collaboration feature called B2B Sync. If you enable this setting, users will not be able to start syncing a OneDrive for Business or SharePoint library or folder that was shared from an external organization. Any shared libraries or folders already being synced will stop syncing. If you disable or do not configure this setting, users will be able to sync OneDrive for Business and SharePoint libraries and folders that have been shared from external organizations. For more info about B2B Sync, see: https://learn.microsoft.com/sharepoint/b2b-sync
Registry
SOFTWARE\Policies\Microsoft\OneDrive Value name: BlockExternalSync
Enabled: BlockExternalSync = 1
Disabled: BlockExternalSync = 0
Export Builder
BETAConfigure the state, scope and options, then generate .reg, PowerShell, Intune and SCCM outputs — or add the setting to a multi-setting collection.
These exports write the registry — this is not a managed GPO. ⓘ
.reg file
Windows Registry Editor Version 5.00
; Exported from gporais.com
; Policy: Prevent users from syncing libraries and folders shared from other organizations
; State: Enabled
; Supported on: At least Windows Server 2008 R2 or Windows 7
[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\OneDrive]
"BlockExternalSync"=dword:00000001More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Prevent users from syncing libraries and folders shared from other organizations
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
$path = 'HKLM:\SOFTWARE\Policies\Microsoft\OneDrive'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BlockExternalSync' -Value 1 -Type DWordIntune XML
No direct Policy CSP / OMA-URI mapping for this policy. Use the Intune Remediation tab, or ingest the ADMX in Intune.Intune Remediation
# === Detection script ===
# Exported from gporais.com
# Policy: Prevent users from syncing libraries and folders shared from other organizations
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\SOFTWARE\Policies\Microsoft\OneDrive' -Name 'BlockExternalSync' -Expected 1 -Kind DWord)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Prevent users from syncing libraries and folders shared from other organizations
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
$path = 'HKLM:\SOFTWARE\Policies\Microsoft\OneDrive'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BlockExternalSync' -Value 1 -Type DWordSCCM scripts
# Exported from gporais.com
# Policy: Prevent users from syncing libraries and folders shared from other organizations
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
# SCCM Configuration Item guidance:
# Create a Configuration Item of type "Setting: Script".
# Discovery script: use the Detection script below.
# Remediation script: use the Remediation script below.
# Compliance rule: the Discovery script output equals 'Compliant'.
# === Detection script ===
# Exported from gporais.com
# Policy: Prevent users from syncing libraries and folders shared from other organizations
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\SOFTWARE\Policies\Microsoft\OneDrive' -Name 'BlockExternalSync' -Expected 1 -Kind DWord)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Prevent users from syncing libraries and folders shared from other organizations
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
$path = 'HKLM:\SOFTWARE\Policies\Microsoft\OneDrive'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BlockExternalSync' -Value 1 -Type DWordBuilding a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.