X1 allows you to control which mailbox to index if you're using multiple Outlook accounts.
1. First enter navigate to Tools > Options > Email > Outlook
2. Uncheck "Ignore Additional Mailboxes"
3. Click Apply, then open the "Select Folders to Scan..." menu
4. Browse your Outlook mailbox accounts, and check or uncheck their respective folders to index or exclude Outlook content within X1.
5. Following your selections, the additional mailboxes will not display in your X1 index until your next scheduled indexing cycle. If you want to index
immediately, please run a manual indexing cycle from Tools>Options>Email>Outlook and select 'Index Outlook Now'