If you occasionally changed the /etc/hostconfig file by adding the PARALLELS=-NO- line, you may get the following error message when attempting to open Parallels Desktop:
"Unable to connect to Parallels Service. Make sure that prl_disp_service is running or check your firewall settings."
To be able to open Parallels Desktop, you need to edit the /etc/hostconfig file.
To edit the /etc/hostconfig file:
1. Open Terminal and enter the following command:
$ sudo vi /etc/hostconfig
2. Enter your password when prompted.
3. Press the I key to be able to edit the file.
Use the arrow keys to move between the lines and Backspace to delete unnecessary symbols.
5. Press Esc when finished.
6. To save your changes and close the file, type
and press Enter.
7. Restart your Mac for the changes to take effect.