When $Configuration['ALLOW_NAME_CHANGE'] = '0', updating personal info doesn't work. The username control isn't placed on the form, but the code is still expecting it to be there when the PHP is doing the name uniqueness check.

The fix is to only perform the uniqueness check when ALLOW_NAME_CHANGE = 1. Here is a patch to People.Class.UserManager.php.

1062,1070c1062,1071
< // Ensure the username isn't taken already
< $s = $this->Context->ObjectFactory->NewContextObject($this->Context, 'SqlBuilder');
< $s->SetMainTable('User', 'u');
< $s->AddSelect('UserID', 'u');
< $s->AddWhere('u', 'Name', '', $SafeUser->Name, '=');
< if ($User->UserID > 0) $s->AddWhere('u', 'UserID', '', $User->UserID, '<>');
< $MatchCount = 0;
< $result = $this->Context->Database->Select($s, $this->Name, 'ValidateUser', 'A fatal error occurred while validating your input.');
< $MatchCount = $this->Context->Database->RowCount($result);
---
> if ($this->Context->Configuration['ALLOW_NAME_CHANGE'] == '1') {
> // Ensure the username isn't taken already
> $s = $this->Context->ObjectFactory->NewContextObject($this->Context, 'SqlBuilder');
> $s->SetMainTable('User', 'u');
> $s->AddSelect('UserID', 'u');
> $s->AddWhere('u', 'Name', '', $SafeUser->Name, '=');
> if ($User->UserID > 0) $s->AddWhere('u', 'UserID', '', $User->UserID, '<>');
> $MatchCount = 0;
> $result = $this->Context->Database->Select($s, $this->Name, 'ValidateUser', 'A fatal error occurred while validating your input.');
> $MatchCount = $this->Context->Database->RowCount($result);
1072c1073,1074
< //if ($MatchCount > 0) $this->Context->WarningCollector->Add($this->Context->GetDefinition('ErrUsernameTaken'));
---
> if ($MatchCount > 0) $this->Context->WarningCollector->Add($this->Context->GetDefinition('ErrUsernameTaken'));
> }

Actually, also tell what version of MySQL you see this in--the query is already written to eliminate the existing user account... and this could be the piece that fails:
SELECT UserID FROM LUM_User u WHERE u.Name = 'test' and u.UserID <> 8

Fixed!

Just in time to see this in 1.1.5