9 to 5 Mac reports that more and more number of users claims that they are experiencing some problems with the newest version of iPhoto’11. Users find some or all their photos disappearing after software upgrade. Somebody looses all or some photo libraries, data while upgrade process.  iPhoto '11 also drops support for older AppleTVs and photo calendars. The only and best solution for these problems is backing up the existing iPhoto libraries and data before starting upgrade.