I took a screenshot of the error and pasted the link below for anyone to see
Is it encrypted?
If it isn't, just open
a copy of the wallet file using a text editor and you should see the seed or a master private key.
Seed should look like this (
just a sample, do not import, do not post yours either):
"seed": "like expose apple child wealth dog enough dress knee gun side damage",
Master private key looks like this:
"xprv": "xprv9s21ZrQH143K2zyhHG1QtJoRbFEmoRFavZPDpdZZcD3y5tCCAUJkUBKeEEMRnMiVYgWb9dJSRb................................................",
If it's encrypted and you know the passphrase, click on "
Wallet->Seed", type your passphrase then the seed will be displayed.
Then create a new wallet "
File->New/Restore", type a wallet name then click next, select "
Standard wallet->I already have a seed".
It's recommended to do all of those while offline.
-edit-If any of the above didn't worked, try to import it to 'Electrum 1.8.1 portable' just to export the seed phrase since you'll only see string of characters as seed in the text file (
for old wallet files).
Download 1.8.1 portable from here:
https://download.electrum.org/ or go to
https://electrum.org/#download and click "
Previous releases".
Copy the wallet file in the same directory as the Electrum portable executable and rename it into electrum.dat.
Open Electrum 1.8.1, click "
Wallet->Show->Seed", then import that to the latest version.
Lastly, even old Electrum wallets or even electrum.dat from electrum should open without issues to v3.3.8 (
I've just tried it and it worked).
But the seed written in the wallet file won't be updated to mnemonics, you have to export it through console/GUI.