What does "invalid share" mean in mining?
An invalid share means the mining pool rejected a piece of work your miner submitted because it did not meet the pool’s rules. It usually means that submission earns no credit, but it does not automatically mean your miner is broken or all your mining work is being wasted.
What a share actually proves
A mining pool lets you combine your mining effort with other people. The pool needs a way to measure how much useful work you contribute.
Your miner repeatedly calculates hashes, which are digital results produced from mining data. When a result meets the pool’s easier work target, your miner submits it as a share. Most shares do not qualify to create a Monero block. They simply prove that your miner is doing work.
The pool checks each submission. If the result is correct, meets the required target, and belongs to eligible work, it can be accepted. If it fails a check, the pool rejects it.
An invalid share is not a damaged coin or a failed wallet payment. It is a rejected work submission.
Why a pool might call a share invalid
The exact meaning depends on the pool’s error labels. Common causes include:
- An incorrect calculation. Unstable hardware, overheating, or aggressive performance settings can cause your miner to produce a result the pool cannot verify.
- The wrong mining setup. Outdated software, an incompatible mining algorithm, or a connection to the wrong pool service can produce unusable submissions. Monero uses RandomX, its mining algorithm.
- Not meeting the share target. A result may fail the pool’s required difficulty, meaning the amount of work a share must demonstrate.
- A duplicate submission. Your miner sends the same work twice. The pool will not credit it twice.
- An incorrectly formatted message. A software bug or connection intermediary may send work in a format the pool cannot process.
If you mine through a browser, the page’s software or the service connecting it to the pool can also be responsible. An invalid-share warning alone does not prove your computer is faulty.
Invalid is not always the same as stale
A stale share is work that arrives after the pool has moved on from the job it belongs to. The calculation may be correct, but the submission is too late.
A slow connection, a brief disconnection, or a paused browser tab can contribute to stale work. A calculation error is a different problem.
Some dashboards group stale, duplicate, and invalid submissions under one “rejected” total. Others list them separately. Check the detailed rejection message before deciding what needs fixing.
What you should do about it
One occasional rejection is not necessarily a reason to worry. Repeated invalid shares deserve attention because they waste processing time and electricity.
Start with these checks:
- Read the miner’s error messages and the pool’s explanation of rejection codes.
- Confirm that your miner supports the pool’s required algorithm and connection settings.
- Update trusted mining software, or reload your browser miner.
- Return any custom processor speed or voltage settings to their defaults.
- Check temperatures and reduce mining intensity if your device gets too hot.
- Investigate your connection if the errors specifically say “stale.”
The bottom line
An invalid share means the pool could not credit that submission—not that you lost coins from your wallet. Look at the specific rejection reason: it tells you whether to focus on calculations, settings, software, or timing.
