Hello all,
Thanks for all of your replies. I learned the lesson the hard way. Luckily that's not all the BTC I have. I still have some BTC stored in my Tresor wallet. I will never store crypto in Metamask ever again. I have reformatted both my desktop and laptop and reinstalled fresh Windows. The only thing I am not sure is that if my iPhone has been compromised? I deleted Metamask app on my iPhone and will never ever use it again on my iPhone. But it is enough? If my iPhone is compromised, there may be other things I need to worry about too. Does any of you have suggestion what I should do about my iPhone? I have iPhone 11 Pro with iOS 14.

I have been storing some crypto in Metamask wallet since early 2021. Last week, I opened my wallet and saw it empty. First I thought it was an error, but after reviewing the transactions, I realized my wallet has been drained out. About 5.6 WBTC (equivalent to 5.6 BTC) was sent out to some unknown address without my knowledge on June 15, 2022. 

Here's the history of my Metamask wallet: I installed the wallet on a desktop in early 2021 and transferred some fund into it. Shortly after, I installed Metamask wallet on my laptop using the same seed. So, I have the same wallet on two PC mirroring each other. A few months ago (around April) I installed the wallet on my iPhone with the same seed, so basically all three devices had the same wallet. Up to that point I had about 126K USD Coin in the wallet. On June 14 I swapped all the USDC for WBTC, with amounted to about 5.6 WBTC. All transactions were done through iPhone. A few days later I opened the wallet on my iPhone and was shocked to see that the wallet was empty. Some transactions were made on June 15, sending all the WBTC and ETH out without my knowledge.

Needless to say, it was a trauma for me. I was scrambling to find out how it happened. Did I download a rogue version of Metamask, or one of my devices was compromised? For the PC, I downloaded it from metamask.io. For the iPhone, I used Apple store. Here's a few things that may give clues to how the attack came through:

1) The fund has been in my wallet for months so if the attackers wanted to take it they could have done so earlier. It must be something I have done lately. One June 13 I downloaded some software and installed it on my desktop. The software was not related to crypto. At the same time, my Norton Security subscription just expired and I didn't renew it right away. So there's lapse of security on my desktop around the time of the attack. The desktop is used on daily basis and it is on most of the time during my work hours. 

2) All the latest transactions was done through iPhone, so I wonder if the attack could be on my iPhone? One thing I notice is that while all the latest activities are shown on my iPhone Metamask wallet, they are not shown on my desktop nor laptop wallet. All the transactions I made on June 14 (to swap USDC to WBTC), and the unauthorized transaction of sending WBTC out, are shown on iPhone, but not on desktop or laptop. Looks like someone has erased the transactions to hide them from me. Though I can view them on Etherscan.

3) I did not turn on the laptop in the week leading up to June 15, the date of the unauthorized transaction. I actually barely used my laptop to access Metamask.

Here's my wallet activities on Etherscan:
https://etherscan.io/address/0xbf0a095f3479847c8bf677e33046a5e7b5dcce94

I learned that I can store my BTC in hardware Tresor wallet and trade through Metamask, instead of storing the coin in Metamask itself. I wish I knew that sooner. I take my consolation in the fact that this is not all the BTC I have. I still have some BTC stored in Tresor wallet. If anyone is storing your coin in Metamask, I urge you to use Tresor instead. Use Metamask to trade only, not to store the key.

There have been talks about central bank digital currency (CBDC), a kind of cryptocurrency that is backed by a central bank. Recently, China is rolling out digital yuan, its own version of CBDC (curiously, it's not using blockchain). Even though China is not the first country to have its CBDC, it's the first major economy to do so. Some people argue that CBDC will make bitcoin become obsolete, as in this article:
https://seekingalpha.com/article/4418567-bitcoin-china-launched-digital-yuan-and-will-change-everything

People who support this view fail to realize that, while CBDC has some characteristics of a cryptocurrency, it is still very much a fiat currency. It can be inflated whenever the government wants to. It is not anomymous (one of the features that crypto users prefer). Users of CBDC do not have the freedom as crypto users do. CBDC may be a great contribution to the economy, but it will not replace bitcoin. In fact, I believe that CBDC may even make bitcoin more valuable. Why? Because with CBDC, it's easier to convert bitcoin to CBDC and vice versa, so people who hold bitcoin may not even need to use an exchange to convert their BTC to fiat, and people who want to buy bitcoin can easily do peer-to-peer transaction without using a bank account.

I long for the day when the Federal Reserve issues the digital dollar. It will make conversion between bitcoin and USD even easier, and we may not need to use an exchange service.

What do you think?

Most people who rush to buy bitcoin think they can get rich fast. They need to know that like any other investment, it take time, patience and faith.

Congratulations!

The whole purpose of cryptocurrency is to be free of any governmental regulation, and we have achieved that goal.

Don't buy a coin just because it's growing fast. Some crypto creators are good at promoting their coins and fool people into thinking their coins have great potential, while in fact they are just another copycat. You should do the research and look into the technical details.

The nice thing about being a crypto billionaire is nobody knows exactly how much you are worth, and the government cannot tax you (unless you cash out your crypto).

I don't think we will ever be free of COVID, but it will become less fatal and eventually it's death rate will be about the same as influenza

Bitcoin was created with purpose of using it as medium of exchange. Now it seems more like a digital asset.

We already have USD Coin. No need for PP coin. It won't make any difference.

In the early days of bitcoin, people kept saying it's a scam. Now those same people are rushing to buy.

80°C is a very high degree to reach, so am I correct to assume that with proper air circulation, you can keep you miners running even in summer when the temperature reaches 38-40°C (100-104°K)?  

I am planning to buy some S19 Pro 110TH/s, possibly up to 10 units. I am undecided whether I should buy new or used ones. New ones are expensive ($15K-$16K now) but I guess I will get back the investment before they start breaking down. Used ones save me a few grands each unit, but I am not sure if I can get back my money before they break down. Since most S19 Pro are less than 1 year old, and I can get them fixed if they break down, maybe it's a better option?

Please advise. Thanks

Thanks for the explanation. So what would be a safe ambient temperature for the miners? In summer when temperature rises to 90+ Fahrenheit how do you keep the miners from overheating?

My friend and I are planning to run some S19 Pro Antminer in his home in Houston, TX. Right now the weather is good for cooling, but in summer the temperature can reach 100+ Fahrenheit, I assume we must install some AC to cool them down? We plan to have up to 10 units in a shed. Do you think running an AC is sufficient?

I am new to mining. Can someone tell me what PCB stand for in this table (Miner normal operating temperature range):

https://support.bitmain.com/hc/en-us/articles/360005088914-Miner-normal-operating-temperature-range

My friend and I are planning to mine bitcoin at his home in Houston, TX. We plan to start with 1-2 Antminer S19 Pro 110TH/s and possibly up to 10 units. Which mining pool do you recommend? Does mining pool size matter. I see that large pools tend to have higher transaction fees. So if I decide to join a smaller pool, is there any disadvantages? Some pools like Genesis Mining or WinMiner even have no transaction fee. Is it worth trying them?

What is the most important factors you need to consider when joining a mining pool?

Please advise. Thanks

I tested all three boards and they seem to work. I wanted to post a screenshot of each board here but there's no such option on this forum. The GH/S (avg) of one board is 4,715, the other two are 4,072 each.

Lately there has been much talk about mining bitcoin with renewable energy. One company in Texas plans to do so:

(this board keeps removing my hyperlink so you can use google to find the following article on CNBC ):
"This Houston tech company wants to build renewable energy-run bitcoin mines across Texas"

One problem with solar energy is that it can only be generate during daytime. So the said company will power down their miners at peak time. That raises two questions:

1) If you powerdown your miners daily, will it damage the machine, or shorten their use life? Since bitcoin ASICs are only profitable for the first 4-5 years of their life and you will have to replace them to stay profitable, if they can last this long I assume it should be OK?
2) Solar power are only available during daytime so if you only run your miners 8-10 hour a day when the power is available, will you be able to make profit?

In my state California, electricity rate is expensive (I pay above $0.20/kwh on average). But California is one of  the best state for solar power so if I want to be profitable with bitcoin mining I have to think solar. Say if I build a mining farm using solar power and I have to power down at sunset, will it be profitable? Using battery to store energy for after-hours is an option but will the profit overcome the cost?

I know the S9 Antminer requires 220v to run, but I don't have 220v outlet now. I am waiting for the electrician to install it, and it won't be done for another week. While waiting for him, I would like to test run my S9 and learn how to set up. Is it safe to do so with 110v outlet?

I bought this machine earlier this year but haven't had a chance to work on it. I paid $210 for it, including the PSU, and am surprised when I see the price is more than doubled now. I know S9 Antminer is not profitable to mine bitcoin now so I bought it for learning purposes before I make any serious investment in mining machines. Why does the price go up?

I believe that this guy is smart enough to keep a backup copy of his wallet, or the recovery seed. It would be stupid not doing so when you have a large amount of bitcoin.

The problem is he cannot move this bitcoin, because if he does, law officers will know that he does have access to the fund and they can arrest him again. Even if he is not arrested when the fund is moved, he will be under tight surveillance and any unusual financial activity of him with be scrutinized. Eventually he must come up with a smart plan to spend his bitcoin. I imagine that he may set up a fake business and act as if his money comes from this business, not from his bitcoin fund.