I installed the latest version of Parallels today (22 September 2016). Parallels tools refuses to reinstall. I have tried a number of times by selecting "reinstall parallels tools" in the Actions drop down menu, but each time I get an error message saying that Parallels tools won't install, and suggesting a reboot. I have tried the options in the Parallels knowledge base, article 8969. The first option (uninstall and reinstall parallels tools) doesn't work because there is no parallels tools installed and the second more complicated option seems to be set up for an older version of windows than windows 10, and anyway the options aren't available eg I can't uncheck items in the startup tab of system config - possibly because you need Tools installed to do this, anyway I can't do it.
Last edited: Sep 22, 2016