diff --git a/screen-recorder.gemspec b/screen-recorder.gemspec
index 23c2547..2e2d051 100644
--- a/screen-recorder.gemspec
+++ b/screen-recorder.gemspec
@@ -29,7 +29,7 @@ Gem::Specification.new do |spec|
 
   spec.require_paths = ['lib']
 
-  spec.add_runtime_dependency 'childprocess', '>= 5.0'
+  spec.add_runtime_dependency 'childprocess', '<= 6.0'
   spec.add_runtime_dependency 'os', '~> 1.0'
   spec.add_runtime_dependency 'streamio-ffmpeg', '~> 3.0'
 end