# Install error : Protocol violation

**URL:** <https://meta.discourse.org/t/install-error-protocol-violation/36444>\
**Category:** Self-hosting\
**Created:** [8 Diciembre, 2015 20:31 UTC](https://meta.discourse.org/t/install-error-protocol-violation/36444 "2015-12-08T20:31:33Z")\
**Posts on this page:** 1\
**Showing post:** 1

<div class="post-metadata">

**Author:** ![ivanrlio](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/ivanrlio/32/48497_2.png) [@ivanrlio](https://meta.discourse.org/u/ivanrlio)\
**Post date:** [8 Diciembre, 2015 20:31 UTC](https://meta.discourse.org/t/install-error-protocol-violation/36444/1 "2015-12-08T20:31:33Z")

</div>

Hi guys,

I am following this guide ([Install Discourse on macOS for development](https://meta.discourse.org/t/beginners-guide-to-install-discourse-on-mac-os-x-for-development/15772)). I’m having an issue with installing Discourse (the same error as, [https://meta.discourse.org/t/install-error-protocol-violation-with-postgresql/35160](https://meta.discourse.org/t/install-error-protocol-violation-with-postgresql/35160)) and have ensured that the ‘config/database.yml’ attribute ‘prepared\_statements = false’.

My versions:

```
➜ discourse git:(master) ruby -v
ruby 2.2.3p173 (2015-08-18 revision 51636) [x86_64-darwin15]
➜ discourse git:(master) rails -v
Rails 4.2.4
➜ discourse git:(master) psql --version
psql (PostgreSQL) 9.4.5

   List of installed extensions
  Name | Version | Schema | Description
---------+---------+------------+-------------------------------------------------------------------
 hstore | 1.3 | public | data type for storing sets of (key, value) pairs
 pg_trgm | 1.1 | public | text similarity measurement and index searching based on trigrams
 plpgsql | 1.0 | pg_catalog | PL/pgSQL procedural language
(3 rows)

```

The error:

```
== Seed from /Users/ivanrlio/discourse/db/fixtures/002_groups.rb
rake aborted!
ActiveRecord::StatementInvalid: PG::ProtocolViolation: ERROR: bind message supplies 1 parameters, but prepared statement "a1" requires 0
: SELECT "groups".* FROM "groups" WHERE "groups"."id" = 0 LIMIT 1
/Users/ivanrlio/discourse/app/models/group.rb:236:in `lookup_group'
/Users/ivanrlio/discourse/app/models/group.rb:222:in `block in ensure_automatic_groups!'
/Users/ivanrlio/discourse/app/models/group.rb:221:in `each_key'
/Users/ivanrlio/discourse/app/models/group.rb:221:in `ensure_automatic_groups!'
(eval):1:in `block (2 levels) in run_file'
PG::ProtocolViolation: ERROR: bind message supplies 1 parameters, but prepared statement "a1" requires 0
/Users/ivanrlio/discourse/app/models/group.rb:236:in `lookup_group'
/Users/ivanrlio/discourse/app/models/group.rb:222:in `block in ensure_automatic_groups!'
/Users/ivanrlio/discourse/app/models/group.rb:221:in `each_key'
/Users/ivanrlio/discourse/app/models/group.rb:221:in `ensure_automatic_groups!'
(eval):1:in `block (2 levels) in run_file'

```

Any help would be much appreciated.

Thanks

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