Hi all, Got up this morning and my iMac 24 had frozen. It does this every now and then and Ive never managed to get to the bottom of it. Rebooted and didnt get my normal signon screen with my photo against my name. Tried to log in but would not allow me. Tried to log on as admin and got the same error. Booted off my backup drive and the machine fired up. Repaired permissions on the primary drive but when I try and repair the drive I get the following messages: --- Failed Invalid node structure Volume check failed Error: The underlying task reported failure on exit. 1 HFS volume checked 1 volume could not be repaired because of an error --- Checked the smart status and this was set as Verified. I can look at the data (not tried to copy anything off as of yet). I just shut the machine down and went to work. What is my best course of action to fix this problem? Are there any utilities that I can use to check the drive? Going to go out today to get a bigger external drive so I can back up anything I can before I start trying to fix things. Any help would be greatly appreciated. Thanks. Glyn.