Copy/paste has also recently stopped working for me. I've read the various entries in the forum, checked the configuration, reinstalled parallels tools, restarted Windows, restarted my MacBook, uninstalled Avast, and re-downloaded and re-installed Parallels. It still doesn't work. I haven't updated Mac OS in a long time, so no changes have occurred there, and the problem has to lie with Parallels. Please issue an update fixing this issue, there are evidently many of us with the same problem.