Comment 8 for bug 518336

Thank you for taking the time to report this bug and helping to make Ubuntu better. The "Global Search" feature in Thunderbird simply indexes all of the mail saved locally so that it can be easily searched within Thunderbird. A separate setting deals with how Thunderbird handles mail on a server, the default being to download a copy and leave the original on the server. This setting can be changed manually by going to Edit -> Account Settings -> Synchronization and Storage. This setting can be changed before the mail is downloaded by selecting "Manual Setup" during the account setup process. However, if you feel that Thunderbird should provide this option in the automatic account setup, or that it should warn users that the default setting is to download all emails, then we can see about submitting a feature request.