Hi, > If I delete the default global address list and offline list and reboot > the server, is it going to be created automatically? The 0x8000010f error is most likely caused by missing OAB(s) (Offline Address Books). It does not get created automatically, you will need to have some OAB or you will continue to get this error. And you may need to clear out the OAB files at the user end as well (where their Outlook is installed) or Outlook will not load new OAB's (not sure why, Outlook should be smart enough to know when there is a newer OAB on the server but anyway...). If you add the default address book back on the server (recommended unless you have some special circumstance) then it won't get rebuild until the next scheduled build, see the database properties in ESM under Recipient container. Typically this is midnight or 5am by default. You can force a rebuild but you have to play silly games with the scheduler that runs the database rebuilds, not sure why Microsoft did not think to have some relatively simple way of rebuilding the OAB address lists - the rebuild warns you that this could take a while if you have many users, but the software could have been written to be able to pre-calculate the estimated build duration and the "Rebuild" options in the ESM should not get so cranky when you ony have 200 or 300 users in the address lists, which is probably true for 95% of all Exchange installations out there. Best regards Mike Salim