This makes me think of a NOFX song called "bath of least resistance"

Who would be allowing it? You and me, people with brown hair? If you are referring to 'the globalized masses,' sometimes it feels like the question of approval of new technologies is sort of a sacred thing in global culture, like rites and rituals in tribal life. Which makes a sort of sense, because technology seems to act as a sort of rite of passage into adult life.

Are there situations where its allowed to erase a memory from someonelse's mind? — LiveAnotherDay

Sure. If I'm part of an army and in another country we've declared war on I'm "allowed" to kill anyone who tries to defend themselves as an "enemy combatant" per direction from my superiors. So. Do you mean is it ethical? Ethics are pragmatically relative anyhow either based on belief that may or may not be true or not. In the eyes of an absolute idea of goodness that plays no favorites? That's debatable.

"The eternal sunshine of the spotless mind"
It is memory that keeps us from repeating our mistakes.

Are there situations where its allowed to erase a memory from someonelse's mind? Imagine if it would be possible where are the borders to who and who not? — LiveAnotherDay

Interesting question. A good way to go about it is to be clear about what is "good" and what is "bad" and then proceed from there.

"Bad" is "suffering", without suffering the word "bad", looses it's meaning, very much like the word "harm" or "problem".

"Good" on the other hand is everything that helps resolve suffering, like being sheltered staves off the harm of homelessness, quality food staves off the suffering of starvation, hunger, appetite and boredom, and a laptop with the ability to visit interesting philosophy-forums staves off boredom and the general craving for mental stimulation.

It comes all down to the avoidance of suffering, so this is key to have in mind to judge the benefits of moral scenarios.

Now back to the question, are there scenarios where the erasure of memories can be beneficial. Absolutely!

If we imagine a group-rape victim, that is traumatized in many ways from this brutal memory, and the perpetrators are locked away or will likely never be found anyway, it makes a lot of sense to take that torturous memory from the rape-victim.

It releases the victim of their suffering, with no downsides.
If they can’t remember it, and didn’t have lasting physical problems from it, it will practically be as if it never happened to them, it would "solve" it.

But just to be sure, you can and should ask them, if they want that.
And if so - relieve them of it. And with consent especially, I see many beneficial ways to use it.

Firstly, even in a society where this is deemed acceptable, it must always be at the discretion of the person having their memory altered in some way.

Even with this consent however, I think this should be a no. hit the nail on the head with this one. Memories are what make us learn from mistakes and experiences, even if they are experiences forced upon us against our will as with the scenario mentioned by . I'm sure many such victims would do anything to get rid of the pain that this memory brings but not the things it has taught them about themselves, the people/society around them and the world as a whole.

Should we erase the crimes of WWII? The Genocide of millions was no doubt tragic but we need the memory of it to ensure that it is better recognised before it happens and to prevent it. Being a holocaust denier is a very damaging thing as many would agree, so why would we think it's ok to erase the memory entirely? Obviously, I'm not saying that we are actually willing to learn from these things, just look at the shit Russia and China are pulling, killing and hurting thousands and no one seems to give enough of a damn to do anything about it. That's for another topic lol...

One also needs to consider the implications of such a technology. Even if we came out with a set of rules and guidelines that must be followed, such as consent, there will always be some governments, criminals and organisations who would ignore these. It would also raise the issue of "If no one knows a crime has been committed because the memory of it has been erased, has the crime still been committed? It's kind of like the age old philosophical question "If a tree falls but no one is around to hear it..."

I don't think it would be necessary. For in many cases which victims are subject to extreme trauma the memory erases itself in order to sustain the well being of the individual... my own past for example.
I was supposedly raised in a meth house and beaten regularly, but I hardly remember most of my childhood memories in which that was the case. I only remember a few bad ones but mostly the good in order to best maintain my sanity the only way my body knows how.

Are there situations where its allowed to erase a memory from someonelse's mind? Imagine if it would be possible where are the borders to who and who not? — LiveAnotherDay

Standard anesthesiology technique. You're sedated but aware, and afterward you don't remember the experience.

https://en.wikipedia.org/wiki/Twilight_anesthesia

Things like trauma and extreme event, if it is known that it will not negatively affect others should be a good basis of where it is good.

The limits on this however may get out of hand and have government simply erasing peoples lives for their own gain if the technology existed

It is not always the case and the trauma example could be used for those with PTSD and such things because they remember

It depends on whether the memory in question poses a threat to someone, including but not limited to the person whose memory it is.

I have a lot of bad memories - situations, random thoughts, urges, and whatnot - that I'd like nothing better than to forget. A targeted memory erasure would be something I don't mind undergoing.

Then what about memories that are dangerous to the person it belongs to. What would armies give for a pill, to be ingested by its spies when capture by the enemy is imminent, that would erase all or militarily strategic memories?