The most common objection I hear when helping people remove their guilt is something along the lines of "Hey wait! I was using that!"
Believing this (or really any variant of "but guilt is good for me!") makes it fairly hard to replace guilt with something more productive.
I've met some people who complain that if they didn't have guilt then they'd do horrible things. I think this is fairly unlikely, and I file it right next to the arguments that say that if they didn't believe in God then they'd do horrible things. Even after dropping your obligations, you will still have something to fight for. Your reasons for not doing things you'd rather not do will remain even after the guilt is replaced.
Others I have met protest that guilt is useful in order to ensure that they won't repeat their failures. Without guilt, how would they learn their lesson? To which I generally say, that's fine, but if it keeps happening then you aren't learning, and it's time to use a different tool instead.
That said, there are lessons that need learning, and there is something sort of like 'guilt' that can help you learn them.
But you can use it even while completely replacing your guilt motivation.
Once upon a time, I had a loose date planned with a girlfriend. She was going to drop by around 21:00 to hang out. I had something else planned at 19:00 that I didn't expect to take too long; it ended up taking many hours longer than expected. There was no particularly convenient point along the way to step out and call my girlfriend and tell her I'd be late… so I didn't. I simply got home at 23:00 at night, opened the door, and saw my girlfriend sitting worried on the bed.
There's a very distinct type of feeling that I experienced, there, which you might call "guilt." Seeing her sitting there on the bed, I suddenly remembered that the anxiety and dejection that she went through was far worse than the slight awkwardness I would have incurred to call her. A compartmentalization in my head broke down, and the part of me that had known she'd been feeling terrible suddenly came into mental focus. My error became obvious. The feeling was something like being punched in the gut.
Afterwards, I also had the opportunity to feel a lingering sense of regret for days.
When I suggest removing guilt, I suggest removing the latter — but not the former. The former is quite useful.
If you worry that, by removing guilt, you will lose your ability to update when you mess up, then I say: update on the suckerpunch. Trust me, it's strong enough. Update immediately when you realize where you failed, and use the terrible feeling to make sure you don't do that again.
Update fully on the suckerpunch, and there will be no need for that lingering regret. Skip to the end, immediately; update as far as you can, the moment that you realize your error. Moping for days doesn't make things better. Updating your behavior does.
There are those who still protest that the lingering regret is useful: if you hurt your friend, you may think that they need to see you spending days filled with regret, or otherwise they will think less of you. You may think that others find it disconcerting to see you update immediately and continue without missing a beat. Some people want to see penance done.
If that is your protest, then I have little to offer you. I can only note that I have seen many groups of friends form a tacit pact of non-excellence, where each individual in the group is reluctant to outperform the others, in fear that high performance will be punished with ostracization. Many have condemned themselves to a life of dissatisfaction thanks to a non-excellence pact. I say: better to inspire your friends than validate their mediocrity.
It can give some people whiplash, to see you update quickly, but I much prefer friends and lovers that encourage skipping to the end rather than those who feel a need to extract their pound of flesh whenever you err. For me, the social cost of updating quickly is well worth the ability to move faster. Your experience, of course, may differ.
Just remember that you won't be able to replace guilt-based motivation before giving yourself permission to do so. For so long as you view your guilt as an aid rather than a burden, for so long as you view it as right and necessary, I cannot help you remove it.
But I can tell you this:
Almost all emotions, I have found a place for. I have long looked upon Spock and Jedi with some dissatisfaction: I am not one to advocate suppressing emotion. Anger has its place and time, as does joy, as does sadness. Awe and fear and cold resolve, I have found a use for.
I have even found a use for that suckerpunch that occurs when you learn you have made a mistake, that you might label 'guilt.'
But the lingering, drawn-out guilt, the persistent regret that drives one to work in fear of it?
I have never once found a use for that.