Microsoft.
Many, many years ago - first task in a new job - "install MS-DOS, Windows 3 and Fortran on that PC".
That meant making specific changes in the install of both DOS and W3.
There were three manual comments about how to do this, one for each piece of software.
They were all different.
And they were all wrong.
Much later, with Windows 10 they made it impossible to do my (software development) job. Never again.