Migration from Exchange 2010 to 365 very slow


I have extremely slow problems during this migration, I applied the policies required to the source:
New-ThrottlingPolicy UCCSPolicy
Set-ThrottlingPolicy UCCSPolicy  -EWSPercentTimeInAD $null -EWSPercentTimeInCAS $null -EWSPercentTimeInMailboxRPC $null
Set-Mailbox <ServiceAccountName> -ThrottlingPolicy UCCSPolicy

But the problem persist.

 EWS throttling in Office 365, disabled.

Problem persist.

the time is 2.5 days for an 8G mailbox,
during previous migrations it was 4 hours maximum
there are no bandwidth problems, there are no network problems, there seems to be a "block" in exchange 2010
can someone give me some advice?
  • Hello Alessandro,


    Thank you for posting to the On Demand Migration for Email (ODME) forum. I understand you are seeing slow migration from an on-premise Exchange 2010 server to Office 365. Two and a half days for an 8GB mailbox does sound considerably lower than expected throughput.


    I understand that you have already set a migration throttling policy. However, we do have our own KB article on setting a throttling policy for Exchange 2010, which includes more parameters:

    How To: Create an Exchange 2010 Throttling Policy for Migration (115828) 


    As far as the Office 365 side, Microsoft does not disable throttling. However, you can request an increased EWS throttling policy for the migration, which will allow for the fastest migration possible. It sounds like you have already requested an EWS throttling policy increase from Microsoft. One thing to keep in mind is that when you request an increased EWS throttling policy, you also request a timeframe, 30, 60, or 90 days. This increased EWS throttling policy will automatically expire at the end of the selected time period, at which time you would need to request a new EWS throttling policy. Here is our KB article regarding requesting an increased EWS throttling policy from Microsoft:


    Request an upgraded Office 365 throttling policy from Microsoft to achieve best migration throughput and performance (265794)


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




    Trevor Taegder

    Senior Technical Support Engineer

    Quest | Support

  • Hello

    thank you for your help.

    New-ThrottlingPolicy ODME_Policy

    Set-ThrottlingPolicy ODME_Policy -RCAMaxConcurrency $null -RCAPercentTimeInAD $null -RCAPercentTimeInCAS $null -RCAPercentTimeInMailboxRPC $null -EWSMaxConcurrency $null -EWSPercentTimeInAD $null -EWSPercentTimeInCAS $null -EWSPercentTimeInMailboxRPC $null -EWSMaxSubscriptions $null -EWSFastSearchTimeoutInSeconds $null -EWSFindCountLimit $null -CPAMaxConcurrency $null -CPAPercentTimeInCAS $null -CPAPercentTimeInMailboxRPC $null -CPUStartPercent $null

    Get-Mailbox -ResultSize unlimited | Set-Mailbox -ThrottlingPolicy ODME_Policy

    it is for ALL mailbox? 

    the guide says to apply the policy to the administrator you use for migration
  • This is the log of IIS

    2021-12-16 15:25:13 POST /EWS/Exchange.asmx - 443 DOMAIN\administrator ExchangeServicesClient/2.2.19527 200 0 0 764
    2021-12-16 15:25:13 POST /EWS/Exchange.asmx - 443 - ExchangeServicesClient/2.2.19527 401 0 0 124
    2021-12-16 15:25:13 POST /EWS/Exchange.asmx - 443 - ExchangeServicesClient/2.2.19527 401 1 2148074254 156