Comment 7 for bug 132741

balsa and other mboxes are not supported yet - they are planned

iowait times can stall your desktop - use vmstat 1 and look at last column wa. This is the percentage of cpu thats idling waiting for IO - consistently high values 90+ will stall other apps

high iowai could be due to the size of indexable content (can you let me know size of files in $Home/cache/tracker) you have or bugs in tracker/kernel/hardware issues