Mojave Common Issues
WiFi: No Hardware Installed, sluggish performance after Mojave upgrade
If your Mac is running slow and/or your WiFi hardware is missing after upgrading to macOS Mojave, You may have an exisiting incompatible config file from a previous version of Mac OSX. Deleting this file will speed up the operating system and restore Wi-Fi functionality.
If you're booting from a usb drive, make sure to edit the file on the right volume.
1. Start the terminal app from Applications/Utilities
2. Check if the file exists, by typing
ls -l /etc/sysctl.conf
If this returns a result like the following, then the file exists:
-rw-r--r-- 1 root wheel 125 21 Nov 2016 /etc/sysctl.conf
If it does not, then your issues are caused by something else
3. Rename the file:
sudo mv /etc/sysctl.conf /etc/sysctl.conf.bak
4. Restart your computer, and you should be all set, or if you've rolled back to High Sierra, you should be good to attempt the upgrade again.
Messages Running slow after Mojave Upgrade
Your Mac can have a corrupted Contacts database.
Signing out and back in to iCloud isn’t fixing anything because your Mac reusing its local database, and thinking that everything is up to date. Updating a contact is what “rebuilds” its entry, allowing it to be displayed.
Try wiping your local cache to force your MacBook Pro to re-download all of your contacts from iCloud.
- Sign out of iCloud.
~/Library/Saved Application State/com.apple.AddressBook.savedState
- Restart your Mac
- Sign Back into iCloud
Your contacts should all download fresh from iCloud.
(Note: Steps 2 & 3 are really the crucial ones, but the Contacts.app doesn’t have much in the way of preferences, so might as well be thorough.)