Why am I getting 'attempt to index nil'?

I am trying to make a saving collectible system by using a Boolean Value called 'regularFound'. I put the value in StarterCharacterScripts, and I can collect the item just fine. However, when I try to save the value with a script, I get the error message attempt to index nil with 'regularFound'. Here is my code:

local store = game:GetService("DataStoreService")
local datastore = store:GetDataStore("Data")

game.Players.PlayerAdded:Connect(function(plr)
	plr.Character.regularFound.Value = datastore:GetAsync(plr.UserId.. "value")
end)

game.Players.PlayerRemoving:Connect(function(plr)
	datastore:SetAsync(plr.UserId.. "value", plr.Character.regularFound)
end)

Any idea why studio thinks that 'regularFound' does not exist?

That error usually happens when an instance doesn't exist or when an instance hasn't loaded yet. What you can maybe do is:

game.Players.PlayerAdded:Connect(function(plr)
	plr.CharacterAdded:Connect(function(char)
		char:WaitForChild("regularFound").Value = datastore:GetAsync(plr.UserId.."value")
	end)
end)

This will wait for the character to load and the regularFound value to load. `

The problem is that boolean values don't support strings, they just support bools. Change the bool value to a string value.

You're welcome.