I have upgrade to 1197 and have observed the following (also occured on previous builds)
Reboot the server PC and start Firefly
Look at the log tab on the status page and it reports ‘failed to open log filename’
Now I am using MS Small Business Server and a remote desktop connection to launch my user session and it is possible that that is the problem. But it looks like somehow, when you log off it doesn’t release a file handle or something.