Thanks. The following rings bells for when I set up Windows 10 originally. It refers to a password, which sounds correct. Unfortunately it states "The user name must be different than any others on the device.". If 'user name' is referring to my profile name on my computer then changing to a local account means choosing a new profile name, which I do not want to do. Have I understood this correctly?
I want to keep my existing profile name.
support.microsoft.com
I want to keep my existing profile name.
Change From a Local Account to a Microsoft Account in Windows - Microsoft Support
Learn how to change your Windows sign in from a local account to a Microsoft account to sync your settings across all your devices.

My Computers
System One System Two
-
- OS
- Windows 11 Pro
- Computer type
- PC/Desktop
- Manufacturer/Model
- HP EliteDesk 705 G5
- CPU
- AMD Ryzen 5 Pro 3400GE
- Memory
- 8GB DDR4 SDRAM
- Graphics Card(s)
- Integrated AMD Radeon Vega 11
- Hard Drives
- 256 GB PCIe NVMe M.2 SSD
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- Operating System
- Windows 11 Home
- Computer type
- Laptop
- Manufacturer/Model
- DELL Inspiron 15-3576
- CPU
- Intel Core i5-8250U
- Memory
- 8 GB DDR4 - 2400 SODIMM
- Graphics card(s)
- Intel UHD Graphics 620
- Hard Drives
- 256GB SK Hynix SC311 SATA SSD