Changing account name

If I use control userpasswords2 to change the username on the account I'm logged into, will that screw things up?

When I did a clean install of Windows 10, logging in with a Microsoft account, it didn't allow me to choose a username, it just used the first part of my e-mail address g_ala

I've dug into things and have been able to change the name on my user folder and on the login screen and other places without any problems, but still g_ala is in here.

That would be a very useful utility, one that fixes Microsoft choosing your username for you, changing it *everywhere* in Windows 10 with one click.

"logging in with a Microsoft account, it didn't allow me to choose a username, it just used the first part of my e-mail address g_ala"
If I only had a dollar for every one this has happened to. :)
The issue is that the device was set up with the g_ala admin profile and no matter what you name it or rename it, it is the default for User folders. Here's how do change the name, as you desire.

You have to create a Local User admin acct (Action Center/All settings/Accounts/Your info/Sign in with local account instead) with the actual name that you want to use, let's say Frank (no need to enter a password, can leave blank).
Now, copy or move the content of all the folders under This PC\g_ala; like Music, Pictures, etc to the corresponding folders under This PC\User\Frank.
After you verify that C:\Users\Frank has all the content transferred properly, deleted the g_ala User while still using the Local User\Frank account. (easiest way is Option 2 in this tutorial, it will ask to keep files under g_ala or not) - User Account - Delete in Windows 10

Under the Local acct\Frank in Action Center, select 'sign in with Microsoft acct' and enter your email details and password. Restart and the correct name and log in details will appear on log-in screen and all folders. Done. C:\Users should now show only the desired name {Frank} and Public
You can keep or delete the Local Account per your desire, the difference being signing in with MS acct will sync OneDrive etc while Local is only for that particular device. Good Luck

Brink has relevant forum tutorials linked in this post - changing administrator

I didn't do it that way. I found a Registry edit that altered the name of the user folder it looked for, and I changed both that entry and the name of the user folder - while logged into the Administrator account.

All is working fine - except for a few things that look to a different place for the name of the currently logged in user.

Win+R, enter control userpasswords2 then on the Users tab there is Administrator in the group Administrators and g_ala in Administrators;Users

I click on g_ala then Properties. I can rename g_ala there.

What happens if I do that? If I change it to Gregg to match the name on the login screen and the name of my User folder?

Will a system restore point save things if changing that screws things up?

Of course the proper solution is for Microsoft to just quit choosing people's Windows 10 user names for them. :P

"What happens if I do that? If I change it to Gregg to match the name on the login screen and the name of my User folder?"

It only changes the user name, like on the log-in screen, not the folder paths under This PC and you'll find that you can't rename the folder under Users. These paths and names are in the registry.

"Will a system restore point save things if changing that screws things up?"

Absolutely create one before proceeding ! But again, especially if your acct is the only one, follow the steps in post 2, I have done this multiple times for people who want to change their User name and folders and the process of creating the correct acct is fast if you choose not to use a password. The most time consuming thing is moving all the content from the undesired name folders to the desired name ones, if you have a lot of content. It saves you from screwing with the registry profiles. Your installed programs will be untouched.

"Of course the proper solution is for Microsoft to just quit choosing people's Windows 10 user names for them."

Agreed ! They do not make it obvious how your User name is created if you use the MS acct that they push hard for you to use at set up time. In the future, in case you do a clean install or set up a device for friend, the best way to insure that their desired name is used, is to Set Up Win10 with Local Acct where you can clearly see user name. After first log-in, THEN go to Users in the Action Center and elect to 'sign in with Microsoft account' which will then retain the desired name AND allow you to sign in either Local or MS in the future with one user name on both, the correct one !

Here's and outside link verifying Brink's tutorials. See the answer under the check mark for Solution, same as ours - onedrive - How to rename the User folder in Windows 10? - Super User