Craigb, she asked if it was safe, and I should have said it's probably "safe," but it's definitely a huge "maybe" on not having issues (some major) with the upgrade.
Saying that only a few people are on here complaining compared to how many are using it, well, how many are just dropping avast! and going with something else, never to even come to the forum? Who knows. Anyway, it's always a "maybe" on whether there will be issues with an upgrade because there are more different combinations of computer systems, programs, and experience levels of people using them than we can count. It seems to me, though, that this particular program upgrade is having more than its share of problems.