Copying to a Microsoft 365 Site Collection requires Custom Scripts to be enabled at the destination

Symptoms

When migrating to Microsoft 365 Groups or publishing sites in Microsoft 365, you receive this error message:

Copying to a Microsoft 365 Site Collection requires Custom Scripts to be enabled at the destination. This setting will be modified prior to the migration.

Index

• Error code
• Details
• Solution - Classic experience
• Solution - Modern experience
  • Microsoft 365
  • SharePoint 2019
  • Copy options 

Error code

Details

Custom script is automatically enabled when running a classic experience migration as a global administrator. SharePoint cannot automatically enable custom script if you do not run the migration as a global admin or if you are migrating to a modern experience.

Note: It is possible custom script is enabled during other actions as well. You can always verify the setting through your Admin Center.

Solution - Classic experience

Run the migration as a global administrator so that no manual action is required on your part to enable custom script.

If you cannot run your migration as a global admin, you must manually enable custom script by following the instructions in this Microsoft article.

Solution - Modern experience

The Custom Script feature cannot be activated automatically in a modern site during a migration. Because of this, ShareGate Desktop is not able to migrate your forms, web parts, and ASPX pages correctly. This can cause some unexpected issues at the destination.

Note: Custom script is disabled in a modern site when it's created in SharePoint, even if you have it enabled at the tenant level.

Microsoft 365

To resolve this in Microsoft 365, you'll need to follow the steps below to activate custom script using PowerShell:

1. Download the SharePoint Online Management Shell.
2. Open a SharePoint Online Management Shell prompt.
3. Run the two following commands:

Connect-SPOService -Url https://YourDomain-admin.sharepoint.com  
Set-SPOSite -Identity https://YourDomain.sharepoint.com/sites/YourSite -DenyAddAndCustomizePages 0

Run your migration again, and everything should be working properly.

You should set Custom Script back to denied after the migration. To do so, you can run the script again, but this time change the -DenyAddAndCustomizePages value to 1.

SharePoint 2019

To resolve this in SharePoint 2019, you will need to follow the steps below to activate custom script using PowerShell:

1. Open a Windows PowerShell or Windows PowerShell ISE window.
2. Run the following script on your Site Collection:

$site = Get-SPSite -Identity "http://yourfarm/sites/yoursite"
$site.DenyPermissionsMask = $site.DenyPermissionsMask -bxor [Microsoft.SharePoint.SPBasePermissions]::AddAndCustomizePages

Run your migration again, and everything should be working properly.

Copy options

If you are unable to use PowerShell to enable custom script, you can run your migration without migrating content that impacts the modern experience.

1. From the migration screen, click Options.
2. Under Configurations, deselect Web parts and Customized list forms.