What is the best way to handle the Google Apps All Mail label during migration?
The best approach is to filter out the All Mail label until the very last pass. The reason for this is that Google has most items in individual labels, but also keeps a copy of all items in the All Mail label.
Without adding this filter, MigrationWiz will have to index the AllMail items label before it can migrate. This will typically be very large, and consequently will take a very long time to index.
We recomnend that you first filter out All Mail, and migrate all the other labels during the Pre-Stage and Delta passes. Then, perform one last Delta pass, having removed the All Mail filter, so that it indexes the All Mail label during this pass and migrates any additional non-labeled items.
Here are the steps to follow to add the filter to your MigrationWiz project Advanced Options. This should be left in place for all passes, apart from the very last pass (where it is removed, as detailed at the bottom of this article).
Here is a screen shot that shows how this will look under your MigrationWiz project Advanced Options:
You can now perform your migration by following the steps in the migration guide that matches your scenario.
After you have completed all passes, you can perform one additional last pass, but with the filter removed. Note: This pass can be performed after your users have already begun using the Destination account.
Follow these steps to remove this filter for the very last pass:
Under Filtering, remove the previously added filter.
Now you can select the items for migration, click Start and select Full Migration, and follow the prompts to start your migration pass. This pass will migrate any additional items that are in the All Mail folder, but not in any other label. This is normally just a few deleted items, and archived items (that have no label). Normally the user is unaware of these items, but it is still best to migrate, for completeness.