Issue #8591 has been reported by chmel (Josef Chmel). ---------------------------------------- Bug #8591: [BUG] Segmentation fault ruby 2.0.0p195 (2013-05-14) [x64-mingw32] https://bugs.ruby-lang.org/issues/8591 Author: chmel (Josef Chmel) Status: Open Priority: Urgent Assignee: cruby-windows Category: platform/windows Target version: ruby -v: ruby 2.0.0p195 (2013-05-14) [x64-mingw32] Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN rails server crashes with Segmentation fault in pure app created with rails new . after installing mysql2 gem like this gem install mysql2 -v '0.3.12b6' -- --with-opt-dir="C:\work\mysqlconnectorc61" On Windows 7 64b with ruby 2.0 64b in C:\Ruby200-x64 installed by ruby installer rubyinstaller-2.0.0-p195-x64.exe, devkit DevKit-mingw64-64-4.7.2-20130224-1432-sfx.exe and mysql connector mysql-connector-c-6.1.0-winx64.msi. without gem 'mysql2', '~>0.3.12b6' with gem 'sqlite3' server runs fine -- http://bugs.ruby-lang.org/