Why is some email dated January 1, 1990? Some Lotus Notes systems incorrectly return email without a creation date, or with a creation date that is in the future (i.e., April 1st, 2053). For most Destination email systems, using an invalid creation date will prevent the item from being created because the creation date is required to be set and valid. To ensure there is no data loss during migration, MigrationWiz will use a default creation date of January 1st, 1990.
Most of the time this problem will only affect Lotus Notes databases which are corrupt. From experience, this issue will typically affect old items originating from older versions of Lotus Notes, probably following an incomplete upgrade process. This said, the correct date of these items may still be stored in the system, so repairing your database may resolve this issue.