Advanced Topics below is from Parallels 10 User Guide. I have reinstalled Parallels tools and still cannot find reference to Coherence Mode. Problem arose because CRTL-C/V or CMD-C/V do not work between Windows 8.1 and OSX 10.10.1. With original installations, as now, all CMD-->CTRL options are checked.
Additionally, when I reinstalled Parallels Tools, the login User was one not required prior to reinstalling Parallels Tools. There seem to be 3 Users, but I am not sure how they were installed; I am the only user of this machine.
With Parallels Tools reinstalled (was it installed?), there is no reference to 'Coherence Mode' with the Parallels icon in the top menu bar.
￼3 When the installation is complete, click Restart to restart the virtual machine or wait for about 2 minutes and it will be restarted automatically.
To edit the settings of Parallels Tools installed in your virtual machine, use the Options tab in the Virtual Machine Configuration dialog.
Reinstall or Update Parallels Tools
To reinstall Parallels Tools:
1 Start Windows (p. 34).
Once Windows starts, if Parallels Desktop is in Coherence mode, click the Parallels icon ￼ in the menu bar and choose Exit Coherence.
2 When Windows boots up, choose Reinstall Parallels Tools from the Virtual Machine menu. This option is available only if Parallels Tools are up-to-date. If Parallels Tools are outdated, you
will see the Update Parallels Tools option instead.
Check Whether Parallels Tools Have Been Installed
You can easily confirm whether Parallels Tools were installed. Start your virtual machine and look at the status bar of its window. If the tip "Press Ctrl + Alt to release the mouse and keyboard" appears in the status bar of the virtual machine's window, this means that Parallels Tools were not installed. When Parallels Tools are installed, you do not need to press any key to release the mouse and keyboard - they are released automatically.