Apple Operating Systems and Devices
https://remotedesktop.google.com
In Finder to display of Hidden files by type Cmd + Shift + . (dot)
To turn on globally type the following command in Terminal:
defaults write com.apple.finder AppleShowAllFiles -bool true
To revert back to hidden append false:
defaults write com.apple.finder AppleShowAllFiles -bool false
To make the Finder change effective type:
killall Finder
If when installing an HP 7520 WiFi printer with HP Easy Start you get a warning that the scanner does not support “Bonjour” then you may end up with a working printer but no scanner!
In most cases this happens because you have a dual band router advertising 2.4GHz and 5GHz on the same SSIDs. In short the HP 7420 only works with the 2.4GHz network.
One solution is to disable the 5GHz network or rename it and only connect the Mac and printer to the 2.4GHz SSID network.
Fit a YouTube video in the browser window as follows:
Normal YouTube Video URL is https://www.youtube.com/watch?v=grItaOxuyTE&t
To watch in a re-sizable window without switching to Full Screen rewrite the above URLas follows:
https://www.youtube.com/v/grItaOxuyTE&t
Append your YouTube video ID to www.youtube.com/v/VIDEO_ID to display a re-sizeable browser window.
In other words replace /watch?v= with /v/ in the normal URL
The steps below are for Catalina but it should be the same for other versions of macOS.
Check hard disk Integrity to rule out disk faults
Boot the computer up in single user terminal. On chime press Command + S and run file system checker and repair
/sbin/fsck -fy
Reboot as follows:
/sbin/mount -uw / reboot
Repair Permissions
Open Disk Utility and choose your main hard drive from the sidebar (in most Macs there will only be one.) Now click on First Aid and Repair Permissions.
In Firefox URL box enter about:config to view | edit your default locale search and language settings:
UK values for above = en.GB, GB, GB, False
This is a work around for setting the Message default font colour.
Create a signature with Mail -> Preferences -> Signature selecting the mail account and + button like the one below in blue or desired colour:
Hello
Regards,
Joe Bloggs
Now when you send a new message this signature will appear. If you insert your message between Hello and Regards it will be blue.
The above diagram shows a home Airport network with wired (RJ-45) Airports in the Sitting room, Reception (Time Capsule) and Study (Loft) and a wirelessly connected Airport in the Conservatory connected to a HiFi system using a audio mini-jack port. Due to the proximity of the Airport HiFi it wirelessly connects to the nearest AirPort Time Capsule in the Conservatory. The wired AirPorts are connected to the LAN using a straight Ethernet cable connected to the WAN 
port and nearest room RJ-45 wall port.