Do I need to re-download Bitcoin Core?

So recently, I had an update for Windows 11 (KB5063878) and ended up uninstalling it. My PC has been lagging since then, and when I checked my SSD, it seems its health took a hit. Now I'm thinking about rolling back to Windows 10. Here's my big question: If I go ahead and install Windows 10, will I need to download Bitcoin Core all over again? Or is there a way to back up my Bitcoin Core files to a different drive and bring them back later? I really want to set up a Bitcoin LND node in a couple of days. Edit: I downloaded Bitcoin Core in prune mode, which is around 20gb.

Backup Bitcoin file to another drive. When you are done with new installation, copy the file and put in the right directory and your Bitcoin core will run without doing another initial block download but you may have to sync to the current block depending on how long you went offline during your new window installation.

You can backup your datadir to an external drive so that when you reinstall Windows 10, you can simply reinstall the Bitcoin Core program and copy the datadir back to your internal drive. Since your node is pruned, it should even fit inside a USB stick, so I don't think you will have to go out and buy any additional hardware. How did Windows 11 decrease the lifespan of your SSD though? I am confused about that.

The question on Bitcoin is answered (copy your date dir to an external drive or usb stick). What I want to add is that in mid-October Win10 will go out of support and then you may want to upgrade again. Plus, I would give more attention/research on what could have caused your SSD issues and your lag, just blaming it on Win11 makes no sense to me. So you may want to reconsider this "going back to Win10". I am telling this because I find your "solution" a wasted effort: I expect you'll go to Win11 soon. Of course, it was just an advice; you do as you think it fits, it's your hardware and your time.

I bought a new notebook with Windows 11 installed. I tried it for two days, and got rid of it. I installed Ubuntu on the drive, and it is much faster and easier to use for my purposes. Copilot and cloud storage, together with all the spyware and vulnerabilities make Microsoft products a non-starter for me.

As reminder, it's just about 1 month and 1 week before Windows 10 no longer receive update. I don't expect average people would bother to pay for extended security updates that least for  3 additional years or switch to IoT Enterprise/LTSC version that receive update until 2032. I also wonder about that since some news state the update may make the SSD vanish/unable to detected after heavy write activity.

You missed this update: Do Not Update Windows 11 (KB5063878 & KB5062660) There was a recent update on window 11 that was causing failures in ssd some weeks ago. https://vt.tiktok.com/ZSAwaqATJ/

Well, should I just backup the data directory? I have 2 directories here, one is the Bitcoin core directory and the other is the data (I think the nodes are downloaded there) directory. Actually, I saw many posts on Facebook about SSD corruption. Many people say that their PCs have turned off while playing games. Also many people say their ssd crashed even, while PCs shutdown. So from there, I assumed that this is a problem with the Windows 11 update. Actually, this problem mainly occurs when transferring files over 50 GB. Since I downloaded the Bitcoin core, which is about 600 GB, this may be the reason for the problem. So I am planning to go back to Windows 10. Yes, I am also thinking of switching to Linux, I have also tried Linux Mint before, but the problem is that I do not like using Linux because I have been a Windows user for a long time. And there is no such support for games in Linux, and there are also problems with Adobe products. But i know Linux is open source and best for security .So  I am thinking of switching to Windows 10 for a few days.

Cookdata already pointed you to another thread about this update KB5063878. It seems that is the reason for your SSD corruption. This is the reason why I don't use Windows 11; it is still new and has many bugs. You're lucky that you don't have your wallet installed because if you had and no backup seed, you already lost your wallet.

What is of big size is the blockchain, not bitcoin core itself. And the blockchain is split into a shitload of smaller files (128 MB), you are in no danger of having 50 GB size. Your windows' backup file or some game related data files are more likely to have been causing issues.

Thank you for mentioning my post here! I initially posted it here in this board, because it would have been helpful given that the majority of people uses windows, but the moderator felt like moving it to the off topic board, donno why!! Anyway, I would like to add that, this update is still causing dead issue! I just saw some people complaining in our local group that they got their SSD's dead! I don't know why windows still rolling this update despite the reports! As I have said previously, trying to move/write big chunk of data will cause the bug to appear! And it seems, you had that update installed, and did exactly what was needed!

The important directory is where the "blocks", "chainstate" and "wallets" folders are. It's what we refer to as bitcoin "datadir". The directory with bitcoin-qt.exe is just your install directory. And depending on how you originally set that datadir, your bitcoin.conf file may have to be moved for your previous config file settings to apply: If you originally set it in the Welcome Screen (1st time use or with --choosedatadir arg), everything should carry over once you point the datadir path to the copied datadir using the new setup's Welcome Screen. It should continue where you left it since the applied bitcoin.conf is also saved there. (simple and easy as long as the copy is intact)But if you relied on a bitcoin.conf file (with datadir= line) located in the default datadir, while the datadir was set to default in the Welcome Screen, you can either; Do exactly what you did in that previous setup (recommended in this case), Or copy that to the new setup's datadir set in the Welcome Screen but remove the datadir= line since it's already set in the Welcome Screen. The gist is, the bitcoin.conf file that Bitcoin Core (GUI) will use is where you pointed the datadir in the GUI's Welcome Screen or --datadir command line option. For bitcoind, it's where you set --datadir, else, it'll use the bitcoin.conf file in the default directory.

Some of information you know it's outdated. These days, many Windows games can run on Linux with no or little configuration. The biggest proof is Steam Deck (portable gaming device) that use Linux. Unfortunately, i still hear running adobe app on Linux is still not user-friendly enough with limited support. From what i understand from some news, over 50GB refers to total write/copy size rather than size of single file. It's also worth to mention that Bitcoin Core perform lots of read/write during sync if you don't have enough RAM capacity to store whole UTXO/chainstate data.