Frequently Asked Questions

Where does Sparrow store data?

Sparrow’s home folder is different depending on the operating system:

Platform Location
OSX ~/.sparrow
Linux ~/.sparrow
Windows %APPDATA%/Sparrow

On Windows, the %APPDATA% folder can be found by opening File Explorer/Windows Explorer, typing %APPDATA% into the address bar, pressing enter. The Sparrow folder will be in the Roaming or Local subfolder.

How can I run testnet?

Generally, you need to run Sparrow from the command line (or set up an equivalent shortcut).

Sparrow has a number of command line options, for example to change its home folder or use testnet:

Usage: Sparrow [options]
    --dir, -d
      Path to Sparrow home folder
    --help, -h
      Show usage
    --level, -l
      Set log level
      Possible Values: [ERROR, WARN, INFO, DEBUG, TRACE]      
    --network, -n
      Network to use
      Possible Values: [mainnet, testnet, regtest, signet]

For example:


> open /Applications/ --args -n testnet


> Sparrow/bin/Sparrow -n testnet


> Sparrow.exe -n testnet

As a fallback, the network (mainnet, testnet, regtest or signet) can also be set using an environment variable SPARROW_NETWORK. For example:

> export SPARROW_NETWORK=testnet

A final fallback which can be useful when running the Sparrow binary is to create a file called network-testnet in the Sparrow home folder (see below) to configure the testnet network.

Note that if you are connecting to an Electrum server when using testnet, that server will need to be running on testnet configuration as well.

When not explicitly configured using the command line argument above, Sparrow stores its mainnet config file, log file and wallets in a home folder location appropriate to the operating system:

Testnet, regtest and signet configurations (along with their wallets) are stored in subfolders of Sparrow’s home folder to allow easy switching between networks.

Once Sparrow is running in testnet, you will need to connect it to server or node that is also configured for testnet. Blockstream run a public testnet Electrum server, which can be configured as follows:

Blockstream Testnet Configuration

Finally, you can receive free testnet bitcoin from a Bitcoin Testnet Faucet like

How can I choose where my wallet is saved?

See the section above. You need to run Sparrow with the -d command line flag. Setting this will cause Sparrow to store its configuration and any wallets at the given location. For example on Windows:

> Sparrow.exe -d D:\sparrow

This feature allows you to store all Sparrow data on removable media making for more plausible deniability.

How do I increase the fee on a transaction?

A transaction’s fee can be increased either by replacing it (RBF), or creating a child transaction (CPFP).

To perform Replace by Fee (RBF), the transaction must:

  1. Be in the mempool (not yet confirmed)
  2. Have all inputs enabled for RBF (this is the default for transactions sent by Sparrow)
  3. Have all inputs from your wallet

If all the above is true, then Sparrow will add a hover icon next to the transaction on the Transactions screen which looks like a hand with a cross above it. You can also right click to ‘Increase Fee’, which takes you to the Send screen with the transaction loaded, from where you can increase the fee (Sparrow may add another UTXO if there is insufficient change).

You can also use CPFP by spending the outputs of the transaction at a higher fee rate.

Failed to bind one of the listener ports

You may see this error if you are:

  1. Trying to connect to a Tor .onion address
  2. Don’t have a Tor proxy configured
  3. Already running Tor externally on your computer

Sparrow is trying to start its internal Tor, and is failing because Tor is already running.

To solve this, either stop the external Tor, or simply use it as a proxy instead. To do the latter, open Sparrow’s Preferences, go to Server, turn on the Proxy toggle, and set the proxy to localhost:9050. Note that if you do this, your external Tor proxy will need to be running for Sparrow to connect.

Your system is missing a dependency for the webcam

If you see this error on a Windows machine, you are probably missing two Microsoft libraries the webcam driver depends on. These standard libraries can be added by installing the Microsoft Visual C++ 2010 Service Pack 1 Redistributable Package MFC Security Update.

Here’s a guide that describes the installation process.

How do I import my Trezor?

If you have been using the Trezor web wallet at, it is likely that when recreating your wallet in Sparrow you need to select the ‘Nested Segwit’ script type.

After this is done, import your Trezor xpub by using the Connected Hardware Wallet option.

Does getting the fiat value leak privacy?

Sparrow gets the exchange rate from the configured exchange rate provider, and then multiplies that with your wallet balance internally. Your wallet balance is never shared externally.

If you have a Tor proxy configured, Sparrow will use it to retrieve the exchange rate. You can also turn it off by configuring ‘None’ for the exchange rate provider in the Preferences.

What is the master fingerprint for a watch-only wallet?

Often, when setting up a watch only wallet only the xpub is known. In this case, it’s safe to use a default value like 00000000 for the master fingerprint. The derivation path can be set to the default for the script type (indicated in the textfield prompt) if not known.

I’m getting the error ‘PKIX path validation failed’ when connecting

This is an SSL error, mostly likely due to an expired certificate. The right way to fix this is to address the error on the certificate and replace it. For a quick fix, look in the certs folder of Sparrow home for a file with the same name as the URL of the server. Delete that file to clear Sparrow’s record of the SSL cert. It will download the cert again on reconnection.

How can I see the log file?

Sparrow’s log file is available in the Sparrow home folder, as sparrow.log.

You can open it by using the Help > Show Log File menu command.

How do I use coin control?

Go the UTXOs screen (just above the Settings), select the UTXOs you want to spend (use Ctrl/Cmd+Click to select several), and click ‘Send Selected’.

You will need to fill in the address to send to and the label on the Send screen.

I’m running on a high resolution screen and Sparrow icons and text are tiny

It’s possible to control the scaling of Sparrow in Linux or Windows by setting an environment variable.

On Linux:

_JAVA_OPTIONS=-Dglass.gtk.uiScale=200% /opt/sparrow/bin/Sparrow

You can also try setting the scaling factor in GNOME more globally:

gsettings set org.gnome.desktop.interface scaling-factor 2

On Windows:

Set the environment variable to whatever percentage of scaling you require (e.g. 200%). Here’s a guide on how to do it.

How do I rename my wallet?

To rename a wallet, first close the wallet in Sparrow. Then go to the wallet file in the wallets folder in Sparrow home, and find your wallet file - it will have the same name, ending in .mv.db. You can now rename the wallet file - just be sure to preserve the .mv.db extension. When you load the file again, the wallet name will be changed.

Is the Apache 2 license open source?

Yes! The Apache 2 license is very similar to the MIT license, which is used by Bitcoin Core. You can read a reasonable summary here: MIT vs. Apache vs. GPL

How can I build and run from source?

Read the instructions here:

How can I report an issue?

Please use the Issues on Github to report an issue. If possible, look in the sparrow.log file in the configuration directory for information helpful in debugging.