Hello ManelC. Let's remove Parallels Desktop completely and reinstall it to resolve the issue. Please quit Parallels Desktop. Then, open Terminal (Finder -> Go -> Utilities -> Terminal) and execute the commands below one-by-one:
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sudo su
NOTE: You will be prompted to enter your Mac password after executing the first command. Due to security measures you won't be able to see the password itself, just type it in and hit return/Enter.
rm -rfd /System/Library/Extensions/prl*
rm -rfd ~/Library/Preferences/com.parallels*
rm -rfd ~/Library/Preferences/parallels
rm -rfd ~/Library/Parallels
rm -rfd ~/Library/Saved\ Application\ State/com.parallels.desktop.console.savedState
rm -rfd /Library/logs/parallels.log
rm -rfd /Library/Preferences/Parallels/
rm -rfd /private/var/db/Parallels/
rm -rfd /private/var/.parallels_swap
rm -rfd /private/var/db/receipts/'com.parallels*'
rm -rfd /private/var/db/Parallels/Stats
rm -rfd /private/var/root/library/preferences/com.parallels.desktop.plist
rm -rfd ~/Applications\ \(Parallels\)/
rm -rfd /Applications/Parallels\ Desktop.app/
exit
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Then, reboot your Mac and reinstall Parallels Desktop.
Last edited: Aug 20, 2017