Some apps like Sophos AV, VMware Fusion, and Dropbox are not functioning properly after upgrading macOS

Certain applications need to install kernel extensions (KEXTs) in order to function properly. This will require explicitly allowing those extensions to be installed

Grant access to the kernel extension

1. Open Apple System Preferences.
2. Open Security & Privacy.
3. Select the General tab.
4. If general settings are locked:
   1. Click the lock icon in the lower-left corner.
   2. Enter your device password.
   3. Click Unlock.
5. Click Allow next to kernel extension that requires approval. 

Troubleshooting

If you have trouble getting the kernel extensions show up in the security & privacy settings, you can try uninstalling the application and then reinstalling the application.

However, if this Allow button is not appearing, you can also approve kexts in recovery mode.

1. Startup the Mac in recovery mode.
2. Click the Utilities menu and select Terminal.
3. Enter the following command:
   /usr/sbin/spctl kext-consent add TEAMID
   Press Enter
   e.g. for Sophos the command would be: /usr/sbin/spctl kext-consent add 2H5GFH3774
4. Close the Terminal app and restart

Here is a list of common Team IDs

VMWare - EG7KH642X6
Dropbox - G7HH3F8CAK
Cisco - DE8Y96K9QP
CrowdStrike - X9E956P446
Sophos - 2H5GFH3774