There was a problem installing Photshop CC 21.1.2 - Error code 127

This error shows up in case the installer is unable to extract the downloaded files due to a permission issue. Its related to the Adobetemp folder, Please go to C Drive or the drive you have windows installed on and  enable show hidden files, you should see a folder called adobetemp.

Right click on adobetemp folder > Security and check the set permissions, see if your user account has read and write permission to the folder, also check the owner set for the folder, make sure you change the owner to your user account. If these steps do not work, enable the Hidden Aministrator account and try installing there, that should work. Post the installation you can disable the hidden admin account.