The migration process time can vary depending on the size of your collection size and drive speed. For larger collections, it is recommended to use Engine DJ on the desktop to perform the migration process.
On average, you can expect the upgrade to take ~20sec for 1000 tracks (12 GB of data) when upgraded on Engine OS hardware. The same-sized collection on the desktop takes ~5 seconds or less.
Note: The test above was performed on an SSD drive. Your results may vary depending on collection size and media device read/write speeds.
The upgrade migration process is only required once per drive or Engine Library.