I just wanted to mine ETH with my CPU. I use Windows 7 64 Bit with ethminer.

I started the cpu miner with a batch

ethminer -t 6 -C -F http://ethereumpool.co/?miner=5@0x17C0Bea7c44*******9569EBA3d9B605CF2@RigCPU

It starts up and starts mining with about .5-.6 MH/s but after about 1 minute i get

Exception -32700 JSON_PARSE_ERROR: The JSON-Object is not JASON-Valid: Database Error

I have no idea how I could solve this.

CPU is an i7 3630QM

3 Answers 3


In reference to this: http://ethpool.org/

"If you receive frequent "JSON-RPC Problem" errors try to increase your --farm-recheck value. You should find a valid share every 1-2 minutes. If it constantly takes you longer to find a share try to lower your hashrate values (minimum is 0.1)."


Ethminer.exe is not allowed to get through the windows firewall.

You must add ethminer.exe to the exceptions in Control-Center -> Windows-Firewall


This might be a problem with that pool... I believe Farm mode (-F) uses a bit of JSON to talk back and forth.

I'd try it with a different pool (nanopool, coinotron, suprnova, etc.) and see if you get the same error.

Confirmed that this is likely the problem: "Geth however can be used in conjunction with ethminer, using the standalone miner as workers and geth as scheduler communicating via JSON-RPC."


Use a different pool.

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