Comment 2 for bug 504253

Thank you for taking the time to submit this bug. Sorry you are having problems with Ubuntu One. I have reviewed your logs and a couple of things jump out at me.
1. There are some utf8 errors. bug 368626 So renaming the files might help this.
UnicodeDecodeError: 'utf8' codec can't decode bytes in position 4-6: invalid data

2. your throttling is turned on but set to 0. bug 455544
 [bandwidth_throttling]
 read_limit = 0
 write_limit = 0
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.

So give those worarounds a try and let us know how it goes. In the meantime i will forward this on to the U1 team, they are already hard at work solving these issues.

thank you,
duanedesign