That error normally means the encryption key has been replaced in the config file or it was changed in an environment variable. Are you using the default database or did you configure n8n to use Postgres / MySQL instead? Any other changes that might have affected this?
Hi! I’ve also just encountered the same issue while upgrading from 0.xx to 1.9. Investigating now, will post back what I found but the story so far is:
Postgres
Running on a docker compose network
Removed N8N_BASIC_AUTH_ACTIVE=true, N8N_BASIC_AUTH_USER, N8N_BASIC_AUTH_PASSWORD from the docker compose service environment variables
Never set N8N_ENCRYPTION_KEY
Directory where n8n is stored is subject to git branches and we switched between branches a few times
OK, some more sleuthing led me to remember that we configured n8n to save the autogenerated encryption key (and other stuff) elsewhere. I retrieved it the key from elsewhere in the filesystem and plugged it into N8N_ENCRYPTION_KEY and it worked.
But that begged the question: why isn’t n8n able to retrieve that file anymore? Then I remembered that part of the 1.0 version bump involved changing the docker user from root to node, so I had to make the following tweak to my docker compose n8n service environment: