If you saw my other posts and threads on the last few weeks then you will understand that Bitcoin Core is screwed up on my PC and I'am struggling and I decided to move to Windows 10 and make all fresh to make I'am good to go .
So , Bitcoin Core don't want to Reindex (at least it take shitload of days) now I want to know if I take backup of wallet.dat and save it somewhere safe , Unistall windows and install the new Windows 10 could I import the wallet.dat ? or that wallet.dat won't be updated because the Reindexing with the network wasen't finished ?
Also what are the wallets that I could import wallet.dat to safely without any issues because I'am thinking to switch to Electrum after the Installation of the new windows .
Yes you can just move the wallet.dat to the new system and put it in the correct folder. You can not use the wallet.dat file directly with any other wallet software. The easiest and safest way is to send the coins via a TX from the old wallet to a new wallet (e.g. electrum). Most newer wallets like electrum do not allow you to import private keys as they would not be covered by the seed. Im not sure if its worth the hassle to fully sync bitcoin core for a single transaction. If you know someone you can trust its an option to let them do it. You can also export the private keys (no need to sync for that) and import them into a temp wallet like blockchain.info or Mycelium and create a TX to your new permanent wallet from there.
I'm not really 100% sure about the technology (i'm learning myself), but if i'm not mistaking, your wallet.dat holds your keys, not your coins...
So, afaik, you can safely take your wallet.dat, even when you're reindexing, reinstall windows, import the file, and you're ready to go
You can easily try it out on the pc of a trusted family member if you're unsure... Just install bitcoin core, import your wallet.dat, and i'm pretty sure your coins will appear once it's all synced (it might take a while)
Yes the coins are actually nowhere. The wallet.dat contains all private keys, the description you left for the addresses and some transaction data if possible. The transaction data might be outdated, but that should not be a problem.