# Uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)

**URL:** <https://www.ruby-forum.com/t/uninitialized-constant-activesupport-mutex-nameerror/165644>\
**Category:** Rails\
**Created:** [April 16, 2009, 1:12am UTC](https://www.ruby-forum.com/t/uninitialized-constant-activesupport-mutex-nameerror/165644 "2009-04-16T01:12:42Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![marcbey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d9b06d/32.png) [@marcbey](https://www.ruby-forum.com/u/marcbey)\
**Post date:** [April 16, 2009, 1:12am UTC](https://www.ruby-forum.com/t/uninitialized-constant-activesupport-mutex-nameerror/165644/1 "2009-04-16T01:12:42Z")

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I’m on debian etch w/ ruby1.8, activesupport-2.3.2, getting this on the  
first line of code which is require ‘active\_support’ :  
/var/lib/gems/1.8/gems/activesupport-2.3.2/lib/active\_support/dependencies.rb:55:  
uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)  
from /usr/lib/ruby/1.8/rubygems/custom\_require.rb:27:in  
`gem_original_require' from /usr/lib/ruby/1.8/rubygems/custom_require.rb:27:in`require’  
from  
/var/lib/gems/1.8/gems/activesupport-2.3.2/lib/active\_support.rb:56  
from /usr/lib/ruby/1.8/rubygems/custom\_require.rb:33:in  
`gem_original_require' from /usr/lib/ruby/1.8/rubygems/custom_require.rb:33:in`require’

Note that this worked as expected on ubuntu (ibix, amd64).

Thanks,

m

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<div class="post-metadata">

**Author:** ![marcbey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d9b06d/32.png) [@marcbey](https://www.ruby-forum.com/u/marcbey)\
**Post date:** [April 17, 2009, 12:38am UTC](https://www.ruby-forum.com/t/uninitialized-constant-activesupport-mutex-nameerror/165644/2 "2009-04-17T00:38:23Z")

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I had the same issue after upgrading rails to 2.3.2 on a Debian  
machine. Updating the rubygems package (apt-get install rubygems)  
fixed it.