After the cutover migration, you'll need to recreate user profiles by resyncing the .OST files for each %BRAND_OUTLOOK_SHORT% ...

After the cutover migration, you'll need to recreate user profiles by resyncing the .OST files for each %BRAND_OUTLOOK_SHORT% profile. You can do this individually on each computer or device. Or, if users have administrative privileges on their computers or devices, you can instruct them to resync their .OST files themselves.