Trouble with Synchro Bitcoin Core - Pruning mode ?

[Camel179]

Hi everyone 

I have trouble with Bitcoin core (v.0.20.10), as i wanted to synchronise to get bitcoins i received long time ago.

- I started a first synchronisation, but when arrived to 30%, i had no space on my laptop (I have a SSD of 250Go), and I tried to activated the pruning mode, by creating in the Data folder a textedit ''bitcoin.conf" with "prune=550" written in it.
I relaunched Bitcoin core and the synch was all gone, starting back from scratch. Moreover, I don't think the pruning mode is activated as it's still taking a lot of space on the desktop.

> could I delete the blocks folders stocked in the data folder in order to create space ?
> How can i correctly activate the pruning mode ?
> Is there any possibility to get the bitcoins without full syncrhonisation, and send them to another wallet ?
> If I do the full synch, how could i stock the blockchain on a external harddrive ?

Many thanks for your help

[ranochigo]

> could I delete the blocks folders stocked in the data folder in order to create space ?

No, you'll likely corrupt the data directory and you'll have to synchronize again.

> How can i correctly activate the pruning mode ?

If you're not very familiar with the syntax for Bitcoin.conf, you can try activating pruning by going to Settings>Option and checking the checkbox to prune the storage.

> Is there any possibility to get the bitcoins without full syncrhonisation, and send them to another wallet ?

Yes but I highly recommend against this.

> If I do the full synch, how could i stock the blockchain on a external harddrive ?

You can point the data directory at an external harddrive by moving and pointing the data directory at the external drive. Use the config file for that.

[jackg]

If you've got your private keys or can find a way to export them in core (try and search for the fastest way).

You can import them into electrum or other wallet software that won't require full node sync (it syncs but it takes about 5 minutes on a very slow machine).

To activate pruning mode itself uou need to ender a number larger than 4000, so you can set it to 4000 and it should activate. If you go down the pruning route, to check it works start core and leave it running for a bit (until the loader screen goes) then close it and check the debug.log file in your data directory (where the config file is) and see if pruning mode has been enabled.

[mocacinno]

--snip--

> Is there any possibility to get the bitcoins without full syncrhonisation, and send them to another wallet ?

Yes but I highly recommend against this.
--snip--

It doesn't have to be a problem per sé... As long as you realise what you're doing...

dumpprivkey "myaddress"
or
dumpwallet "filename"

executed from the console or the cli should export either the private key belonging to the funded address, or all private keys in your wallet...
These key(s) can be imported into many wallets (like jackg already said: electrum works really well).

BUT.... you have to realise 3 things:

• The private keys will be sent to stdout (dumpprivkey) OR to an unencrypted ASCII file (dumpwallet). This is unsafe... You should look at your wallet as "potentially compromised" after exporting
• It's possible other people still have an address of yours. Always keep the wallet file...
• You have to make sure you export the private keys for all funded addresses... If you forget a private key, those funds will not be "restored" in electrum. It's a pretty big job to check all addresses ever created by your wallet on an explorer, especially for bigger wallets, but if you're not going to sync, checking every address is something you might consider doing

[Camel179]

> could I delete the blocks folders stocked in the data folder in order to create space ?

No, you'll likely corrupt the data directory and you'll have to synchronize again.

> How can i correctly activate the pruning mode ?

If you're not very familiar with the syntax for Bitcoin.conf, you can try activating pruning by going to Settings>Option and checking the checkbox to prune the storage.

> Is there any possibility to get the bitcoins without full syncrhonisation, and send them to another wallet ?

Yes but I highly recommend against this.

> If I do the full synch, how could i stock the blockchain on a external harddrive ?

You can point the data directory at an external harddrive by moving and pointing the data directory at the external drive. Use the config file for that.

Ok, so I've already deleted few files, maybe that's why it started again..

could you detail how to activate the prune mode please ?

Basically I'd just need to transfer the bitcoin folder which is currently in Application support to an external harddrive ? Then I can delete the one in my desktop without any risk ?

[ranochigo]

could you detail how to activate the prune mode please ?

I've specified it in my post actually. Go to Settings>Options at the top and you should see the options to change the config. You can access bitcoin.conf through there too and know which configs are active.

Basically I'd just need to transfer the bitcoin folder which is currently in Application support to an external harddrive ? Then I can delete the one in my desktop without any risk ?

Always backup your wallet.dat first. After moving your data directory, you have to modify the config file to specify the new path of the data directory to follow. Or else, the client will simply make a new data directory in the original place and start synchronizing again.

[Camel179]

If you've got your private keys or can find a way to export them in core (try and search for the fastest way).

You can import them into electrum or other wallet software that won't require full node sync (it syncs but it takes about 5 minutes on a very slow machine).

To activate pruning mode itself uou need to ender a number larger than 4000, so you can set it to 4000 and it should activate. If you go down the pruning route, to check it works start core and leave it running for a bit (until the loader screen goes) then close it and check the debug.log file in your data directory (where the config file is) and see if pruning mode has been enabled.

I'll try to do the synch in the right way for now..

Whe i try to enter prune=4000 in core i have this message : Method not found (code -32601)
I've checked the debug.log, nothing about prune enabled.

In the db.log i have this though :
"wallet.dat: unable to flush: No such file or directory
txn_checkpoint: failed to flush the buffer cache: No such file or directory
wallet.dat: No such file or directory"

[ranochigo]

could you detail how to activate the prune mode please ?

I've specified it in my post actually. Go to Settings>Options at the top and you should see the options to change the config. You can access bitcoin.conf through there too and know which configs are active.

Basically I'd just need to transfer the bitcoin folder which is currently in Application support to an external harddrive ? Then I can delete the one in my desktop without any risk ?

Always backup your wallet.dat first. After moving your data directory, you have to modify the config file to specify the new path of the data directory to follow. Or else, the client will simply make a new data directory in the original place and start synchronizing again.

Thank you, got it !! there is actually nothing written in bitcoin.conf >.<

How can I specify the new path of the data directory ?

Hmm I haven't resync on Windows for quite a bit but IIRC, removing the data directory should result in the client asking you to specify one during startup. Try renaming the %appdata%/Bitcoin to something else and start Bitcoin Core. If it prompts you to specify an alternative data directory, go ahead and do so. If it doesn't then just rename the folder back and it'll work the same.

[Camel179]

Allright thank you !

I've managed to enable the pruning mode.

Though at some point, Core goes in "reindexing blocks on disk" and the loading line (in blue) goes empty (maybe because I deleted some blocks folder in the application support?)

I'd like to do a dumpprivkey but then they asked for the passphrase, and when I enter it i have : "Error: Error parsing JSON:in"

 

[mocacinno]

Allright thank you !

I've managed to enable the pruning mode.

Though at some point, Core goes in "reindexing blocks on disk" and the loading line (in blue) goes empty (maybe because I deleted some blocks folder in the application support?)

I'd like to do a dumpprivkey but then they asked for the passphrase, and when I enter it i have : "Error: Error parsing JSON:in"

 

Were you working from the debug console or the cli?
Either way, it's not

Code:

dumpprivkey

but

Code:

dumpprivkey "myaddress"

Did you include your address?

IIRC (it's been a while since i messed around with importing/exporting), you need to execute
walletpassphrase "passphrase" timeout
to decrypt your wallet in memory before exporting private keys...
But like i said, it's been a while since i last did this action, it's coming from my memory which is sometimes wrong...

[Camel179]

Yes that's what i'm doing but they're saying incorrect password..

Although, while synchronising bitcoin core, I have the feeling that some transactions that should appear don't.. and it's stucked at 4 years and 44 weeks

[BitMaxz]

Yes that's what i'm doing but they're saying incorrect password..

Although, while synchronising bitcoin core, I have the feeling that some transactions that should appear don't.. and it's stucked at 4 years and 44 weeks

That's pretty bad if you get an incorrect password while dumping keys.
To be able to dump private keys you must put the exact password that you use before.

If you can't remember the exact password then you can recover the password by using BTCrecovery tool.
You can follow the full guide here https://github.com/gurnec/btcrecover/blob/master/TUTORIAL.md#btcrecover-tutorial

Or try to crack the password by using the John The Ripper.
The guide can be found here Bitcoin2john.py password recovery guide

Or use a recovery service like https://walletrecoveryservices.com/
I don't know if they are safe but most of the trusted users here on the forum telling that walletrecoveryservices.com is legit.

[Camel179]

Yes that's what i'm doing but they're saying incorrect password..

Although, while synchronising bitcoin core, I have the feeling that some transactions that should appear don't.. and it's stucked at 4 years and 44 weeks

That's pretty bad if you get an incorrect password while dumping keys.
To be able to dump private keys you must put the exact password that you use before.

If you can't remember the exact password then you can recover the password by using BTCrecovery tool.
You can follow the full guide here https://github.com/gurnec/btcrecover/blob/master/TUTORIAL.md#btcrecover-tutorial

Or try to crack the password by using the John The Ripper.
The guide can be found here Bitcoin2john.py password recovery guide

Or use a recovery service like https://walletrecoveryservices.com/
I don't know if they are safe but most of the trusted users here on the forum telling that walletrecoveryservices.com is legit.

Thanks, that might help at some point

[jackg]

I'll try to do the synch in the right way for now..

Whe i try to enter prune=4000 in core i have this message : Method not found (code -32601)
I've checked the debug.log, nothing about prune enabled.

In the db.log i have this though :
"wallet.dat: unable to flush: No such file or directory
txn_checkpoint: failed to flush the buffer cache: No such file or directory
wallet.dat: No such file or directory"

Not sure if this got responded to yet but you can't run the prune in core you'd have to git it as an argument as core starts up or add it to the conf file.

And I think you've meesed up typing the drive in, i'd check you've copied it correctly (and for example use quotation marks around it if it's got spaces in it).