Expected Behaviour email date range

Need confirmation on the behaviour for scenario below.


Migration starts for user A, option selected is to migrate ALL Email (no date range filters applied). 


Migration completes successfully.  However there are unforeseen issues so MX switch-over did not go ahead for x weeks.


As x weeks have passed, User A needs to be migrated again, however what option should be chosen:


a) Migrate with ALL Emails
b) Migrate using Date Range - set start date to 1 day prior to previous successful migration and end to date in future

Will choosing option b) be quicker than option a) or does it not make any difference?

Will choosing option b) still cycle through all previous emails and migrated and skip as they were already migrated or will the tool only start looking at email from the date ranges specified ?

  • Hello,

    Thank you for posting in the On Demand Migration for Email (ODME) forum. I understand you have questions regarding using date filters in multi-pass migrations with ODME.

    In your scenario, when migrating a user again weeks after the initial full migration these are the expectations:

    a) Migrate all email - This will work and ODME will not create duplicates. However, ODME will need to verify that each and every item was migrated by checking the target mailbox. There will be a performance penalty for selecting this option.

    b) Migrate using a date range - This option would provide the best performance as ODME will completely skip all mail outside of the selected date range and will not check the target mailbox to verify email outside of the range was migrated. However, if you select this option, we would recommend selecting a date range that overlaps the previous successful migration by at least 1 day, as you suggested.

    Please let me know if you have any additional questions or need any additional clarification.

    Trevor Taegder
    Senior Technical Support Engineer
    Quest | Support