The problem isn't that the local account isn't valid (otherwise you wouldn't be able to sign in to it). Your problem is that it is a Standard user account, not an administrator. The fact that you can perform the install when signed in with your Microsoft account means that your MS account is an administrator.Update: This is a windows account issue.
I was able to install a piece of software by switching accounts. Apparently this local account isn't valid to the windows security system, but the microsoft account I used to set up the device works to install new software....
Are you sure the local account is corrupt? I would normally agree with you on this diagnosis, but in this particular case it appears that the PC was initially configured with a single Microsoft account that is an administrator, then a second standard account was created. It is this standard account that sees no other local administrator accounts to offer for use in UAC.You can further demonstrate that fact by trying to run anything as an Admin. You will get the same diagram with its Yes button missing / greyed out.
That posted diagram has bothAre you sure the local account is corrupt?
I agree. I have now tested a clean install of W11 with an initial MS account and just one local account that's a standard user. When using the local account UAC should be asking for the PIN of the MS account. Follow Try3's advice and make a new local administrator account NOW....it is not behaving in a normal manner.
You need to use that existing Admin [MS] account to create a local, password-protected Admin account & write its password down somewhere secure yet accessible.
Do it now. Before you do anything else. Before you even read the next line....