Invalid State Check refers to a situation where a transaction or operation does not match the expected conditions or rules of the blockchain. Each transaction is based on a state, which includes account balances, transaction histories, and smart contract conditions. When a node processes a transaction, it verifies that the current state supports it. If the transaction tries to access funds or execute logic that isn’t permissible based on the existing state, it results in an Invalid State Check.This error is crucial for maintaining the integrity of the system. If nodes allow invalid transactions, it can lead to inconsistencies, double spending, or even exploitation by malicious actors. Invalid State Checks serve as a safeguard, ensuring that only legitimate and verified transactions proceed. It ultimately helps enforce the rules that keep the ecosystem secure and functional.