diff --git a/README.md b/README.md
index ef55037..4314677 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,7 @@ launch `MassBuilderSaveTool-<version>.exe`.
 
 1. Install the 64-bit (`x86_64`) version of [MSYS2](https://www.msys2.org/) in its default path (`C:\msys64`), and
 update it fully.
-2. Run `pacman -S git mingw-w64-ucrt-x86_64-toolchain mingw-w64-ucrt-x86_64-cmake mingw-w64-ucrt-x86_64-ninja`.
+2. Run `pacman -S git mingw-w64-ucrt-x86_64-toolchain mingw-w64-ucrt-x86_64-cmake mingw-w64-ucrt-x86_64-ninja mingw-w64-ucrt-x86_64-zlib`.
 3. In a `URCT64` shell, type `git clone https://github.com/williamjcm/MassBuilderSaveTool`.
 4. Type `cd MassBuilderSaveTool && git submodule init && git submodule update && mkdir build && cd build`.
 5. Type `cmake -GNinja -DCMAKE_BUILD_TYPE=Release ..`