The steps must be followed precisely. No exclusions, retention adjustments, etc. may be performed during the process!
Until the final Backup Copy Job is running, no new backup may be created! That means during the migration, the primary backup must be paused!
For point 3 (Transfer): To move the data from the intermediate repository (e.g., a USB drive) to the hardened repository, we used “File Copy” in the Veeam VBR GUI. It is important that the entire subfolder (= backup job name) is copied. The files must not be modified during this process.
Immutability is not active immediately after the transfer. It is only set for the chain once the primary backup job runs again for the first time and subsequently automatically triggers the backup copy job. From that point on, the immutable flag is applied to the chain.