I bought a WD my book for mac 1TB, towards end of Jan. I have a 2008 13" unibody Macbook running Snow leopard 10.6.2. the external HDD had been working perfectly fine with time machine, backing up regularly as it should without any issues. However today I ran into my first problem, where it simply got stuck on 'indexing backup' for several hours. After losing patience I used disk utility which confirmed there was a problem, and told me the disk could not be repaired and needs to be formatted. Luckily I was still able to access the disk and was able to copy over a few important files. I just formatted the disk using disk utility and i am running a fresh backup as I write this. My question is whether this is a warning sign of impending hard drive failure, or is this a perfectly normal occurrence that happens every so often? I'd rather act now than wait and lose anything important because of a dodgy hard drive.