Blocking a bad ElectrumSV server

Roger Taylor
2 min readAug 14, 2023


At the time of writing, some wallet users have a broken server known to their wallet, and it is giving an unexpected response and causing all server connections to break.

This article is intended to show how to block a broken server the hard way until we are able to make a new tested release.

Find your data directory

On Windows this will be something like:

c:\Users\<your user name>\AppData\Roaming\ElectrumSV

On MacOS and Linux this will be in your home directory as:


Find the config file

In your data directory you will see a “config” file.

Open this in a text editor and search for “”.

The as yet not blacklisted problem server.

Make sure ElectrumSV is not running. Close it if it is, otherwise this change will be overwritten when it next exits and it will never see it.

Change the “last_blacklisted” value from 0 to 16919763430. You will note that this is a time many years into the future. This will prevent the broken server from being selected until March 3rd, 2506.

The indefinitely blacklisted problem server.

Save the file. Run ElectrumSV, and you should be able to connect to the legitimate servers again.

Final notes

We are making this more resilient and ensuring the fix for it does not introduce any further problems before we release it.