Yes, it’s true--it's possible that operating system updates can break compatibility with existing applications and functionality. And this really applies to both the PC and the Mac.
Although regular operating system upgrades are tested thoroughly, they have been known to break compatibility with some applications, so that things that may have worked before an upgrade no longer work afterwards.
It seems like Microsoft and Apple have come a long way in trying to make sure the upgrades do not break things. Both systems create checkpoints when they upgrade your system and you can usually remove an upgrade if it breaks something. But problems still occur, and the best approach is to make sure you have important information backed up.
Our advice is to use the automatic upgrades so your system does not become vulnerable to viruses and other problems. On the other hand, this technique only works if you ensure that you have a current backup.
Use Time Machine on your Mac and Windows Backup to insure that all of your important information is always backed up.