Deactivate a Gem - “you have already activated rake 0.9.3.beta.1, but my Gemfile requires rake 0.9.2”

Question

I\'m trying to run a migration but I keep getting the error message that is:

rake aborted! Undefined method prerequisite for nil:NilClass.

It s

Answer 1

One other way that worked for me was, went to the Gemfile.lock and changed Rake version from 0.9.2.2 to 0.9.3.beta.1.

Answer 2

Try to remove your Gemfile.lock file and run bundle install again.

Answer 3

I had the same issue and solved with the help of links below. They can help understanding some concepts regarding this specific question and how and why to use bundle exec rake db:migrate.

You have another option to use gem uninstall rake and then select the version you want to remove.

Read Before installing rails 3.1

Rake 0.9 and gem version constraints by David Chelimsky