After upgrading my Ubuntu 10.04 LTS I had an error window at every boot up session. The message advised me about:

Could not update ICEauthority file /home/username/.ICEauthority

ICEauthority is the Inter-Client Exchange (ICE) Protocol that allows  authentication, negotiation, setting up and taking down connections between programs. In few words, if two programs have the same cookies, they will talk and exchange data through ICEauthority.

To fix this matter open the Terminal and type:

ls -al

Then you find a line similar to this:

-rw——-  1 root        root           35226 2011-10-06 00:24 .ICEauthority

This means that your profile (username on a Linux OS) is not allowed to manage ICEauthority and you have to gain full permission to solve the boot up problem:

sudo chown username:username ~/.ICEauthority

Where username is your user profile on Linux.

Then type:

sudo chmod u+rw ~/.ICEauthority

To check if you succeeded, type again:

ls -al

and this time you will find a line like this:

-rw——-  1 username username    35226 2011-10-06 00:24 .ICEauthority

That’s all!