So I dumped my wallet.dat...

[tsoPANos]

OK In the process of migrating to multibit, I dumped my entire wallet.dat file to a txt file with json format.
But there's a little problem. There are literally hundreds of addresses in there with no balance.
For me it looks like bitcoin core creates them intentionally for an unknown reason.
The problem is that I don't know if I should import them into multibit.
Also, there are some transaction data inside the json file. Should I do something with that?

Any help will be appreciated 
Thanks

[1715376738]

1715376738

[1715376738]

1715376738

[shorena]

OK In the process of migrating to multibit, I dumped my entire wallet.dat file to a txt file with json format.
But there's a little problem. There are literally hundreds of addresses in there with no balance.
For me it looks like bitcoin core creates them intentionally for an unknown reason.

It does. This way you dont have to unlock your wallet.dat every time you need a new address or the wallet needs a change address. There should be ~100 spare addresses.

The problem is that I don't know if I should import them into multibit.

If you dont use your bitcoin-core wallet any long, just import those that are not empty. If you still have bitcoin core running, enable "coin control" and see which addresses still have unspend outputs ("coins on them").

Also, there are some transaction data inside the json file. Should I do something with that?

Any help will be appreciated 
Thanks

Not sure about the TX data. Maybe they are old TX you did? IMHO I think they should not be relevant. Keep them anyway, I could be wrong.

[DeathAndTaxes]

An address with zero balance (technically no unspent outputs) can exist for one of two reasons.

The first is at shorena indicated above the qt wallet will maintain a keypool of unused addresses to ensure backups are instantly out of date and to have addresses ready when you need them.  Depending on how you dumped the wallet you should be able to identify the keypool addresses.   As these have never been used there is no reason to migrate them to the new wallet.  If you can't identify the keypool addresses you may wish to migrate them to be safe.

The second reason for an address having zero balance is simply because you received funds at that address in the past, and then spent them.  Thus today they have zero balance.  Should you migrate them?  Well it depends on if you expect to receive funds with that address again.   If you don't then there is no reason to migrate them.  If you do and the address isn't migrated over then you will be unaware that you received funds.   This is yet another reason why getting in a habit of never reusing addresses makes everything simpler.  An example would be if you have a signature address posted somewhere on some website.  Today that address has a zero balance but if that address will receive funds in the future (because you forget to update it) then you probably want it in your new wallet right?

A more efficient (IMHO better) way to do this would be to not "migrate" the keys from your old wallet.  Create a new multibit wallet and get an address from it.  Using QT send all coins from your existing wallet to the new wallet.  At this point your QT wallet should have zero balance.  If you need any of those addresses for some special reason then just migrate those over.  If you can't identify a reason then don't migrate it over.  The more addresses you migrate over the larger and more bloated your new wallet will be.  Now if you need them that is one thing but if you don't well you are just bloating it for no reason.

Regardless of what you do be sure to backup the original wallet.dat (and "backup" implies the file exists in more than one location).  If you do something wrong well you haven't permanently lost funds as long as you have access to the original keys in the wallet.dat.

[tsoPANos]

First of all, thank you both for the time you dedicated at helping me.
I learned many things by reading your posts.

Back to the topic...
I imported my addresses in electrum.(I know this is a bit silly as I won't be able to recover my keys with electrums seed)
But I prefer electrum over multibit. Anyway, electrum synced in a few moments but I came up with a new problem.
My balance was less than it was shown on my bitcoin-qt. Actually, electrum show 0.02 btc less.
After that, I imported my addresses on blockchain.info wallet in order to see my balance.(watch only addresses)
Sadly, blockchain.info shows the same balance as my electrum wallet.(Again, 0.02 btc less than bitcoin-qt)
Is there a posibility that some addresses from bitcoin core "key pool" hold my coins?
Is there another logical explanation? 

And again, thank you all!

[shorena]

-snip 0.02 missing-
Is there a posibility that some addresses from bitcoin core "key pool" hold my coins?

Yes, the logical explanation why this happened would be change. When you spend an input you have to spend all of it. E.g. you only have an unspend input of 0.15 BTC and want to send 0.13 BTC to X. I leave the fees out for simplicity. You make a new TX send 0.13 to X and the client internally sends the rest (0.02) to a change address. This will show if you inspect the TX on the blockchain.
Depending on the client used the change is send to the same address the input came from or it generates a new address.
AFAIK bitcoin core makes a new address/takes one from your pool unless you set a custom change address.

Is there another logical explanation? 

And again, thank you all!

Another explanation would be that while scanning the blockchain electrum (your new wallet) made a mistake and missed one or more inputs. But the first explanation is more likely IMHO.

[tsoPANos]

-snip
Depending on the client used the change is send to the same address the input came from or it generates a new address.
AFAIK bitcoin core makes a new address/takes one from your pool unless you set a custom change address.


Another explanation would be that while scanning the blockchain electrum (your new wallet) made a mistake and missed one or more inputs. But the first explanation is more likely IMHO.

Oh thanks. I will try to send all of my btc from bitcoin-qt to a new electrum address.

Good work with your arg puzzle ebook btw! 

[shorena]

-snip
Depending on the client used the change is send to the same address the input came from or it generates a new address.
AFAIK bitcoin core makes a new address/takes one from your pool unless you set a custom change address.


Another explanation would be that while scanning the blockchain electrum (your new wallet) made a mistake and missed one or more inputs. But the first explanation is more likely IMHO.

Oh thanks. I will try to send all of my btc from bitcoin-qt to a new electrum address.

Good work with your arg puzzle ebook btw! 

Sending your coins is allways the safest option

Thanks, there will be a final version - not sure if today though.