Mac Desktop "Flashing"

Is your desktop doing the following :

This indicates that your network User Folder has one of the following problems:

We will verify that your Network Home Folder exists.
We will verify that your Network Home Folder is correctly set in AD.
We will verify that your Network Home Folder is visible to the Mac OS.
You are using an local account which needs to be added to an exception list.

Please contact the helpdesk.

Once they fix the issue, the problem will stop.