File sharing failure

I entered my file sharing files and selected everyone but these settings keep disappearing.
Can you help me sorting out this problem?

When / under what circumstances do they disappear?

I have the same problem. Once I click "OK" after adding the folders I want to share, the window closes down. However, the chosen folders do not become available for other users, and when I go into File Sharing again, the folders I previously chose to share, are no longer listed under File Sharing.

Thanks for your comment!
All of a sudden and without my interference it just started working fine. I ended up not knowing what the problem was and how to solve it.
But the worst was other users complaints about it and trying to explain didn't really help. Except in one case - the user understood and let me download from him. Bless him!

bigwave, which build are you using? Any chance I can look at the problem through TeamViewer?

Thanks but, although I have done nothing, it started working properly.