Comment 10 for bug 448093

candtalan,
there is a bug related to bandwidth throttling i noticed yours was marked on = True
 read_limit = 0
 write_limit = 0
 on = True
The problem is that setting the bandwidth preferences to the defaults (clicking on the checkboxes and not changing the values, leaving them 0) results in the read and write limits to be set to -1. The workaround is to delete the ~/.config/ubuntuone/syncdaemon.conf, restart the client, and don't set the bandwidth settings to the defaults.

The U1 team is working very hard to take care of the few bugs. Thank you for your bug reports and all the information you provided us.
duanedesign