I would like to run the migration wizard without limiting the emails to 10MB. However when I enter regedit on me machine, under HKCU\Software\Zimbra\ there is no registry key for MaxAttachSizeMB.
I'm not all that familiar with changing settings in the Registry Editor. Should I just be creating a new entry of type REG_DWORD, with MaxAttachSizeMB as the name and a value of 0?
Thanks in advance for your help.
Yes, you should just create the new entry and set it to zero. You will also need to change the settings on your server, change the values of zimbraMtaMaxMessageSize & zimbraFileUploadMaxSize to zero or any max size you like - don't forget to change the settings to something reasonable when you done the migration.