I have Time Machine running in 10.6.2, with my USB hard drive connected to an Airport Extreme dedicated to Time Machine. It backs up my iMac. Everything has been working perfectly, until today when I started Time Machine to look at an older file, and the fancy space-age interface showed that there no backups before this moment. I closed TM and opened the TM disk, and all the backups were there, being done hourly as usual up until only a few minutes before. Yet TM still doesn't seem to know that the backups it is making are there. I never had this problem when the drive was connected directly to my iMac. Is it related to the Airport Extreme? Is there a way of fixing this without formatting the drive and starting over with TM? Thanks for any info.