Fixers typically come in after caretakers/custodians and try to reinvigorate a formerly vibrant-turned-stagnant enterprise. Unfortunately, most companies make the mistake and hire a fixer from within, which is no different than just having yet another caretaker/custodian.
Intel continues to make that mistake. Paul Otellini (former CEO of Intel) was an Intel insider and followed Craig Barrett, himself a caretaker/custodian. Unfortunately, I think Intel made the same mistake once again by promoting yet another insider (Brian Krzanich) to the CEO position. As did Microsoft. I sincerely hope that Satya Nadella fixes things in Redmond; however, my observation is that a Fixer needs to be an outsider and no better example in recent memory than Lou Gerstner (IBM).
If successful, Marissa Mayer (Yahoo) could turn out to be an accomplished fixer. More often than not they get confused with surgeons (the next type outlined below) and even though there are overlaps they are not the same. As noted above, typically fixers follow caretakers/custodians and are usually a stalling enterprise's last opportunity to get things right.
Fundamentally, fixers need to be superb strategists because that is the core issue — loss of vision, which is almost exclusively followed by confusing strategy. And more often than not fixers don't always implement massive layoffs, they work on crystalizing the long-term strategic direction. Mark Hurd, had he stayed at HP, could have been a great fixer but we will never really know the answer to that. However, if the problems cannot be fixed, it's time to call in the next type — surgeons.
As the name implies, surgeons are usually brought in to 'cut-the-fat-but-keep-the-muscle', which is easier said than done. I call them surgeons because, fundamentally, they use a knife as their main tool. Typically, surgeons are either former CFOs, COOs or GMs that only look at spreadsheets and cut off what they feel is either a losing proposition or a non-productive asset in terms of profits. These types are operatives that perfect their skills at places like GE, GM, Proctor & Gamble, 3M, Bain & Co., etc.
Think Mitt Romney and you get the picture; no passion, no emotion, no inspiring 'let's-kill-the-competition' speeches. They come in, shake your hand, look you in the eye, tell you what needs to be cut and just do it. Bottom line, they are needed and, for the most part, get the job done, but if they don't it is time for the next type to come in and save the day.
This is a special group and pretty rare for it requires entrepreneurial DNA, which is not common in the corporate management ranks even within companies that were founded by builders. The key difference between a savior and a fixer is that the latter has time but a savior has zero time; the enterprise is either doomed (due to numerous successors who mismanaged its fortunes) or about to become history.