Under certain hardware configurations, when attempting to Reset this PC on a system running Windows 10, build 2004, the reset attempt fails with the following error:
There was a problem when resetting your PC. No changes were made.
As a workaround for this issue, do this:
Open an elevated command prompt. To do this, click Start, type Command Prompt or cmd in the Search box, right-click Command Prompt, and then click Run as administrator. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.
Type the following command, and then press Enter:
dism /online /cleanup-image /restorehealth
Reboot your system, and attempt Reset this PC again.