We recently completed a full SPO-to-SPO migration across two tenants after a company acquisition, and I wanted to share what actually worked, since most generic guides don't cover the messy real-world stuff.

First, inventory everything before touching a single site. We used PowerShell scripts to map out site collections, permissions, and content types, but honestly, the manual effort of tracking down orphaned permissions and broken inheritance ate up more time than expected.

Second, don't underestimate metadata and version history. A lot of native tools (including the built-in SharePoint Migration Tool) either strip version history or handle it inconsistently. If your organization has compliance requirements around audit trails, this is a dealbreaker.

Third, plan for throttling. Microsoft's API limits will slow down large migrations no matter how good your network is, so build buffer time into your project timeline.

What actually saved us was switching to a dedicated migration tool instead of relying purely on native options. We ended up using DRS Softech Tenant-to-Tenant Migration Tool, which handled permissions mapping, metadata preservation, and incremental syncs far more reliably than the manual PowerShell + native tool combo we started with. It also gave us better visibility into migration progress and error logs, which made troubleshooting much less painful.

When planning a SharePoint Online to SharePoint Online migration, keeping track of tasks, file mappings, and migration notes is essential. An Online Notepad helps teams quickly organize important information, create checklists, and collaborate more efficiently throughout the migration process. It’s a simple tool that supports better planning and reduces the chance of missing critical steps.