The installer fails because this command returns an "Access denied" error:

"cmd.exe" /c echo C:\win64__343420342033353438.msi > "C:\Users\james.marcus\AppData\Local\\OrnatrixMayaSetupFilepath.txt"

How can it happen that the installer cannot write to the %LOCALAPPDATA% directory (C:\Users\james.marcus\AppData\Local) ?
Is it possible that the directory doesn't exist? Or maybe the username is wrong?

What is the Windows version?

Ivan Kolev (Software Developer, EPHERE Inc.)

E-mail: ivan.kolev at ephere dot com

Discord: ikolev

Both the plugin and the installer rely on the standard per-user application data directory on each OS. On Windows this directory is defined in the registry and the LOCALAPPDATA environment variable. The directory should exist and be writeable to all applications that run under the user account. Please verify that this is the case.

Marsel suggested that another possible cause is that the file already exists and is not accessible, either locked by another application or set to read-only. It seems less likely, but still something to consider.

Ivan Kolev (Software Developer, EPHERE Inc.)

E-mail: ivan.kolev at ephere dot com

Discord: ikolev