Microsoft has removed the Network Location aware feature for Printers in Windows 10 and changed its behavior. Windows 10 now sets the last selected printer as the default printer. This can get irritating at times. If you are looking for a way to stop Windows 10 from changing your default printer, you can use Windows 10 Settings app or edit the Windows Registry.
Default Printer keeps changing
From the WinX Menu, open Settings > Devices > Printers & scanners.
Scroll down a bit till you see a setting Let Windows manage my default printer.
When this setting is turned On, the default printer is the last used printer.
Toggle the switch to the Off position.
Set your default printer in Windows 10
Now go set your default printer. You will see the entire list of printers a little above this setting.
Select the printer and click the Set as default button.
Windows 10 will not change it again, even if you use another printer.
Use Registry to set the default printer
If for some reason this does not help you, edit your Registry and see.
Run regedit and navigate to the following key:
Change the value of LegacyDefaultPrinterMode from the default 0 to 1.
Having done this, set you default printer again.
Hope this helps.
See this post if you find that the Printer icon is not showing in your Desktop, Control Panel, Devices and Printers.