I have a 27" iMac, one year old, Lion 10.7.4 (it's the i5, 8 Gb RAM). Since some months, I'm experiencing a lot of system issues. FOr instance, Finder crashes; after a Time Machine backup, the mac is unable to do the incremental one (once it cannot find the disk, the second time it cannot create a directory, and so on); and other similar issues, such as unable to print, etc. Everything goest back to normal if I restart the mac. I don't know what to do or check. I did repair permissions and check the disk, but this did not resolve my issues. I don't know whether this can be something related to Lion, to some hardware component, some legacy software (I got this mac last year in May, with Snow Leopard - and updated later to Lion). What would you do? Format the disk and do a fresh Lion install and then recover my data from Time Machine? Or check something else first? Any suggestion is largely appreciated.