I had set up file sharing between our two macs in our home (both 10.6) with no problems. But our iMac's disk blew out and was replaced, with 10.6 reinstalled. Now I find that the iMac can see my MacBook Pro, but when I try to enable file sharing on the iMac, the checkbox for File Sharing refuses to take a check: it briefly displays a - sign then reverts to blank. I have triple-checked that the security settings are the same on the two machines, and that the file permissions for the listed files are okay (ie, the same on the two computers). I presume I am missing something on permissions, but I am at a total loss as to what. I would appreciate suggestions.