Fixing "server is lagging" in ElectrumG

In ElectrumG version 3.2.1, it’s possible for the local block header database to get corrupted or stuck on a bad branch.

Sometimes, this will resolve itself. Other times, you’ll see a message like:

Server is lagging

or a perpetual


message for hours, even though the sync should only take minutes.

This problem can be fixed by deleting the blockchain headers and letting ElectrumG re-sync them from the servers. Here’s how:

  1. Exit ElectrumG. (On Windows, Quitting the wallet isn’t enough; that just shrinks the app. Make sure to right-click and Exit from the task bar.)
  2. Navigate to your ElectrumG data folder.
    On Windows, it’s normally in C:\Users\<usernme>\AppData\Roaming\ElectrumG (see note below)
  3. Delete the blockchain_headers file and the forks folder.
  4. Start ElectrumG again.

Do not delete the wallets folder! That’s where the critical information is for accessing your wallets and coins. If in any doubt, make a backup copy of your wallets folder.

After restarting, ElectrumG should repeat the Bootstrap process and then re-sync the block headers from an ElectrumX server. This may take a couple of hours; on my run-of-the-mill desktop & internet connection, it took under two hours for over 600,000 block headers to sync.

note: If this is not where your ElectrumG folder is, then from the ElectrumG menu, do a File - Open and see where your wallets folder is. The default is inside the ElectrumG data folder, so this will show you where that is. But again, do not delete the wallets folder!