What will happen if 2 bitcoin clients are launched at once with the same wallet on a virtual machine and just in Windows?

Question

Information Security

Hello, I apologize in advance if my question is lamer and chaotic, but there is nowhere else to ask somehow.
Since 2012, I have been mining bitcoin for 50BTC. I mined 8.6 coins, of which 0.1 was donated by thepiratebay, I sold another 0.2 on the exchange, taking into account commissions, I should have had 8.29875 BTC left. It is this figure that my client displays, all transactions in the "transactions" tab are beautifully and correctly shown there: one transaction for pirates for 0.11 BTC and 3 transactions for the exchange for 0.0501, 0.0511 and 0.10005 BTC (with a commission as displayed by the client).
Recently, I decided to transfer bitcoins to a virtual machine, re-downloaded the latest version of the client, removed the default empty wallet.dat from there and copied my own (I regularly backup to a USB flash drive). I have been waiting for synchronization for several days, now 4 weeks are behind me, the balance is 7.8399 and 0.45885 has not been confirmed. I decided to look at my address on the blockchain and saw an amazing picture. I thought that I was robbed by a Trojan, because. final balance 6.9 BTC.
https://blockchain.info/address/1ECziqG66MdpoKjzXp...
All incoming transactions are deposits to the wallet from the mining pool. But what about the outgoing ones is not clear. Let's say the oldest outgoing transaction is 1 BTC - where does it come from? I threw exactly 0.1 to pirates with a set commission of 0.01, where and why did another 0.89 go and where is 0.01? And why was it not displayed on the balance sheet in the client all these months? What do 2 addresses next to each other mean in the destination of the transfer, where does the second address come from?
Then, further - I threw 3 transactions on the exchange - 0.0501, 0.0511 and 0.10005 BTC (total 0.2 BTC and commission). Where does the left spending on obscure wallets come from? And again, why is the balance of 8.29875 BTC still shown in one and the second client (it has not yet been synchronized on the virtual machine)?
And yet, what threatens if 2 bitcoin clients with the same wallet are launched at once, on a virtual machine and just in Windows?

Answer 1

And I, like many others, got 260 BTC for 50BTC instead of 0.01 BTC. Only now they can’t be removed - just a number in the profile, no more.
In general - read here: " forums.overclockers.ru/viewtopic.php?t=495303 ".