Transaction Error (Wrong Amount) through MyMonero Wallet?

Question

Good Afternoon,

at 7am MET i sent 50XMR through mymonero wallet to bf exchange. transaction confirmed quickly (around 8am MET) and the CORRECT deposit of 50 XMR showed up in my exchange's wallet.

Since then, until now (6.5hrs later) mymonero wallet is showing that i sent 149.91XMR instead of 50XMR.

Also the Balance in Mymonero is deducted by the 149.91XMR.

I double and tripple checked wallet and payment id's - everything is correct.

Is it a known bug or what could it be ?

thx

Answer 1

MyMonero deducts the full input amount from your balance once you send a transaction. It'll normally correct once the transaction is mined. However, MyMonero is currently under heavy load and therefore might not be able to correct properly.

To go into more detail. Let's say you received an 100 XMR from an exchange, a service, or someone who you traded with. Subsequently, if you make a transaction, of 50 XMR, it'll use that 100 XMR output as input. Thus, you have a transaction with 1 input (100 XMR) and 2 outputs, i.e., a 50 XMR output (minus the fee) that goes back as change to you (the sender) and a 50 XMR output that goes to the recipient. Once the transaction is sent, MyMonero will first deduct the full 100 XMR input from your balance. Then, once the transaction is mined, it'll correct the balance by "recrediting" the 50 XMR change.

Note that you can verify whether the change output was sent back correctly to your address by using this guide:

How do I, as a recipient, verify that my transaction actually arrived?

You have to use the private view key and the public address of the sending wallet in order to decrypt / verify the change output.

P.S. If you have trouble grasping the concept of inputs and outputs, think of them like bills. Let's say you received $20 from your grandma for your birthday. This $20 is the output you initially receive. Subsequently, you use that $20 to buy some groceries worth $10. You hand the cashier your $20 bill and will get $10 back from him/her. In this "transaction" the $20 bill is used as input, the $10 you have to pay for groceries is the output that goes to the recipient, and the $10 change you get back is the output that is sent back as change to the sender.