Instructions for Building the Zotero Client assume a POSIX-compliant system capable of handling symbolic links. These instructions will work out-of-the box on most Linux and macOS systems, but Windows requires a few extra steps.

1. Install Node.JS (version 8 or newer) and Cygwin. During Cygwin setup, in the “Select Packages” step, select the following additional packages to install: “git”, “p7zip”, “python27”, “python3”, “wget”, “zip” and “unzip”.
2. Run Cygwin Terminal as Administrator (right click → Run as Administrator). Run the following commands in that Cygwin terminal, in a single session.
3. Force Cygwin to use native windows symlinks:

   export CYGWIN="winsymlinks:nativestrict"

4. Clone the Zotero source code, Zotero XPI build scripts, and standalone client build scripts. Zotero source code is cloned but not checked out (i.e. no actual files are created):

   git clone --config core.symlinks=true --no-checkout https://github.com/zotero/zotero zotero-client
   git clone --recursive https://github.com/zotero/zotero-build
   git clone --recursive https://github.com/zotero/zotero-standalone-build

5. Change to the source code repo, check out required files, and install Node.js modules:

   cd zotero-client
   git checkout HEAD package.json package-lock.json
   npm install

6. Check out the remaining files, creating valid symbolic links:

   git checkout -f HEAD
   git submodule update --init --recursive

   Note: If you are seeing here errors of the form “error: unable to create symlink […]: Operation not permitted” then you are not running Cygwin as an administrator (see step 2 above).

7. Now continue with instructions on Building the Zotero Client, beginning with step 3.