diff --git a/README.md b/README.md
index c55f71f..5b5f9c9 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ __pdf_unlock.py__ removes security features from pdfs, to allow unrestricted pri
 
 ## Installation ##
 
-[Ghostscript](https://ghostscript.com) and [Poppler](https://poppler.freedesktop.org/) are required.
+[Ghostscript](https://ghostscript.com) and [Poppler](https://poppler.freedesktop.org/) must be in your `PATH` environment variable.
 
 **Windows**:  
 https://www.ghostscript.com/download