Currently I am unable to log into the Management Section of my site if I select http://example.com/user. If I go to http://example.com/admin/reports/status I am then able to log in.
Now if I attempt to make any changes none of my changes are saved. Then if I attempt to add content it does not save.
If I look at my recent log entries I find "The directory sites/default/files/xmlsitemap is not writable, because it does not have the correct permissions set."
There is no xml file located in this directory.
My site has been up for about 2 years and I have had no problems