Microsoft
MicrosoftChristianSchindler , yes, sometimes it can be difficult to identify the type of hold, I completely understand that. We normally use this guidance from How to identify the hold on an Exchange Online mailbox | Microsoft Learn. We talk about holds not being supported in part 1 of the article. And sometimes, we may provide exceptions to some types of holds (litigation holds), better to open a case with us when in doubt: Introduction to Cross-Tenant Mailbox Migrations - Microsoft Community Hub.
Normally, Test-MigrationServerAvailability is pretty verbose now regarding the holds applied, I remember it pointed out DelayedHolds in one of my recent tests. But in the end, support cannot recommend removing the holds for the purpose of migration, we can help if customers decide they want it removed and have issues identifying / removing them.
