Another service operation is currently in progress

When trying to install Symantec Endpoint Protection the following error may popup:
“Aanother service operation is currently in progress”

Try a reboot first, if not possible or problem still exists, try the following:

1. Open Windows Registry Editor. Click Start > Run, type regedit, and click OK.
2. Back up the registry.
   Note: For Windows Registry backup and restore instructions, see How to back up and restore the registry in Windows.
3. In the left pane, navigate to the following key:
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionInstaller.
4. In the left pane, right-click on the Inprogress key, and click Delete.
5. Click Yes to permanently delete the entire Inprogress key and all of its subkeys.

Source: https://support.symantec.com/en_US/article.TECH218138.html