Bullguard is askimg for manual approval. How is this done?

First, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This user tip describes what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is desshoigned solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Also, unless you're using a true VPN tunnel, such as between you and your employer's or bank's servers, they are useless from a privacy standpoint: Public VPN's are anything but private.  

Uninstall Avast and Bullguard according to the developer's instructions. If you have any of the other "cleaning", "optimizing", "speed-up" or anti-virus apps on your Mac uninstall them also?

First, see if "Bullguard" and "Avast" provide uninstallation instructions. If they do, follow then.

But, even if they do or don't, follow this procedure:

1. Drag the App(s) to the Trash & Empty the Trash.
2. Restart the Computer into Safe Mode, login, and restart back into normal mode.
3. Use Find Any File to search for "Bullguard" and "Avast" and delete any files.
4. Restart the Computer back into Safe Mode, login, and restart into normal mode.

Follow these steps for ALL anti-virus Apps, "cleaner" Apps, etc.

From here, I'd consider to Reinstall macOS to repair or reinstall any files that the anti-virus Apps may have corrupted, deleted, modified, etc. If you're doing this, be sure you have a backup first!

Cheers,

Jack

If it was on the Mac before you got it, I suggest you follow the directions here:

What to do before you sell, give away, or trade in your Mac - Apple Support

Who knows what other cruft is lurking there?

Boot into Safe Mode according to Start up your Mac in safe mode - Apple Support

NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

Download and run the shareware app Find Any File to search for any files with the application's or the developer's name in the file name.  For Bullguard software you'd do the following search(es): 

1 - Name contains bull guard

Any files that are found can be dragged from the search results window to the Desktop or Trash bin in the Dock for deletion.

FAF can search areas that Spotlight can't like invisible folders, system folders and packages.  

Reboot normally when done.

Have you tried the instruction in this Bullguard site: How do I uninstall BullGuard from my device?

Return Bullcrap and get your money back. macOS already has built-in security and third party junkware is not required or recommended.

see > https://www.apple.com/macos/security/

Do not install the software, it's unnecessary and will likely cause a great deal of interference on your Mac. Simply keep your Mac OS up to date when new updates are released and you'll be fine.

First try downloading and running the free version of Malwarebytes. It was developed by a long time contributor to these forums and a highly respected member of the computer security community.