Interesting Dispel Magic Questions

[RSP]

So, its still a weapon, but doesn't exist while disapated. So it can't be dispelled then, because it doesn't exist to be targeted then?

Or you can target the caster, at dispel it whether it is present or not?

A weapon is created throughout the duration, whether it’s solidified or dissipated. I don’t know why you default to “it doesn’t exist” when the rule says it absolutely exists.

Nothing says the dissipated shadow isn’t targetable. Maybe it’s like a small cloud of shadow waiting to be reformed. But either way, it still exists.

The shadow blade persists until the spell ends. It's simply not visible once it dissipates. Furthermore, dispel magic does not require you to see the creature, target or magical effect in order to dispel it. So even if it is no longer visible, it is still able to be dispelled by targeting the sword.

As I stated above, nothing in SB’s description states it’s invisible or otherwise undetectable when dissipated. If it is determined at a table to be invisible, I’d imagine the magic is still detectable by Detect Magic. Likewise, as you say, Dispel Magic doesn’t require the target to be seen, just that it’s within range.