Is there any problems with .json account backups? I can’t get my accounts up due to a “invalid format: File account should be an array”

General Frequently Asked Questions
1

The error occurs because Polkadot-JS now expects account backup files in array format [{…}] rather than the older single-object format {…}. The fix is straightforward: wrap your JSON content in square brackets. old way:

{"address":"5GrwvaEF...","encoded":"0x...","encoding":{...},"meta":{...}}

new way:

[{"address":"5GrwvaEF...","encoded":"0x...","encoding":{...},"meta":{...}}]

i.e.

  1. Add [ at the very beginning of the file

  2. Add ] at the very end of the file

  3. Save the file