Back in the day, a company I worked for had a very “manual” deploy process—basically, whoever deployed it (me) had to be sure to follow a 7 step process to the letter, or else Bad Things Would Happen. One time, I accidentally skipped a step or two, and Bad Things were happening, and to make it worse, I couldn't figure out what they were.
There was, however, a working version of the code sitting in the directory alongside this horrifically broken monster. I knew the configs were correct because they had been working not 5 minutes ago, and I hadn't changed them. So I updated a symlink (this was on Linux/Apache, but it would apply on IIS/Windows too), and everything was happy again, though using a slightly older codebase.
There was, however, a working version of the code sitting in the directory alongside this horrifically broken monster. I knew the configs were correct because they had been working not 5 minutes ago, and I hadn't changed them. So I updated a symlink (this was on Linux/Apache, but it would apply on IIS/Windows too), and everything was happy again, though using a slightly older codebase.