1.You could use PowerShell to block a user's own OneDrive site access.
Import-Module Microsoft.Online.SharePoint.Powershell -DisableNameChecking $AdminSiteURL = "https://tenant-admin.sharepoint.com" $OneDriveSiteURL = "the user's own OneDrive site URL" Connect-SPOService -Url $AdminSiteURL –Credential (Get-Credential) Get-SPOSite -Identity $OneDriveSiteURL | Set-SPOSite -LockState NoAccess
2.You could block sign-in for a user so that he cannot log into OneDrive and SharePoint.
Go to Microsoft 365 admin center -> Active users -> Select the user -> Block sign-in.
How to Disable OneDrive for Business in Office 365-SharePoint Online?
How to properly deactivate a user in Office 365 and SharePoint?
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