How to Change Open Files Limit on OS X and macOS

Posted on by Andy

To check the current limits on your Mac OS X system, run:

$ launchctl limit maxfiles

The last two columns are the soft and hard limits, respectively.

Adjusting Open File Limits

To adjust open files limits on a system-wide basis, you must create a configuration file. It is a property list (aka plist) file in /Library/LaunchDaemons/limit.maxfiles.plist that contains the following XML configuration:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
    <dict>
    <key>Label</key>
    <string>limit.maxfiles</string>
    <key>ProgramArguments</key>
    <array>
      <string>launchctl</string>
      <string>limit</string>
      <string>maxfiles</string>
      <string>200000</string>
      <string>200000</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>ServiceIPC</key>
    <false/>
  </dict>
</plist>

This will set the open files limit to 200000. The file must be owned by root:wheel and have permissions -rw-r–r–. This permissions should be in place by default, but you can ensure that they are in place by running:

$ sudo chmod 644 /Library/LaunchDaemons/limit.maxfiles.plist