alembic.util.exc.CommandError: Can't locate revision identified by - Flask-migrate Error

You are getting this error because in your database there is a table named alembic_version which contains previous migrations names created by Flask-migrate. 

To get rid of the error Follow Steps

1. Find alembic_version table in your database by running below command

SELECT * FROM alembic_version;

2. Remove this table from databse by executing below SQL QUERY

DROP TABLE alembic_version;

Now you can run your commands of initialize database and migrate commands.

python manage.py db init


python manage.py db migrate

You will not get error this time because it will create new alembic_version table in database which will contains new migration info.