How to launch the same Rider version multiple times as standalone processes?

Background/Situation

This How to open several windows of JetBrains Rider describes how to open multiple Rider windows for different projects. It supposes Rider windows will be spawned by a single frontend process (rider64.exe) and will be sharing the frontend process memory.

Question

Is there a way to run multiple standalone instances of Rider in parallel (in dedicated processes)?

Answer

Yes, it is possible by making a custom .bat file that will launch Rider using a dedicated idea.properties that declares another IDE directory path.

Sample steps on Windows:

• Find the path to rider.bat script: {RiderInstallPath}/bin/rider.bat

  • The path to Rider installation home can be found from Rider for e.g.: Help | Diagnostic Tools | Special Files and Folders -> Right-click the "IDE Installation home" -> select "Copy Path"

• Make a directory that will be holding IDE configuration files, e.g. C:\Area\RiderThirdInstance ;

• Create config, system, log, plugins directories under that directory;

• Create C:\Area\RiderThirdInstance\idea.properties file with content:

  idea.config.path=C:/Area/RiderThirdInstance/config
  idea.system.path=C:/Area/RiderThirdInstance/system
  idea.log.path=C:/Area/RiderThirdInstance/log
  idea.plugins.path=C:/Area/RiderThirdInstance/plugins
  

• Create a C:\Area\RiderThirdInstance\LaunchAnotherRiderInstance.bat file with the below content:

  @echo off
  
  rem Set this to your Rider installation directory. Spaces are allowed:
  set "SCRIPT_RIDER_INSTALL_DIR=C:\Replace This\Placeholder"
  
  if exist "%SCRIPT_RIDER_INSTALL_DIR%\bin\rider.bat" (
      set "RIDER_PROPERTIES=C:\Area\RiderThirdInstance\idea.properties"
      echo "Launching a standalone Rider instance.."
      start "" "%SCRIPT_RIDER_INSTALL_DIR%\bin\rider.bat" %*
      exit /b
  )
  
  echo FAILED: The %SCRIPT_RIDER_INSTALL_DIR%\bin\rider.bat is not found.
  echo(
  echo Double-check the SCRIPT_RIDER_INSTALL_DIR variable set in the script. 
  echo The install directory path can be copied from Rider: 
  echo * Select Help ^| Diagnostic Tools ^| Special Files and Folders;
  echo * Right-click the "IDE Installation home" row;
  echo * Select "Copy Path";
  echo(
  echo Then open this script for edit and paste the clipboard content into 4th line: 
  echo   set "SCRIPT_RIDER_INSTALL_DIR=C:\Replace This\Placeholder"
  

• Save the script and launch it.

This way one can launch another fully-fledged Rider instance. Note, there will be no user settings and project history from the start. It is a clean launch.

These steps can be repeated multiple times to run as many Rider instances as needed.