Reinstall re-runs the installation that set your server up. It is the right answer to a handful of problems and a very expensive answer to everything else, because of what it does on the way.
Reinstall overwrites the server files with a fresh install. Depending on the setup this can replace configs, jars and startup files — and a reinstall that goes further than you expected is not undoable. Take a backup and download it first. Five minutes now against everything you have built.
When it is the right call
| Situation | Reinstall? |
|---|---|
| Changing to a different server version | Yes — that is what it is for. |
| Switching Paper to Fabric or Forge | Yes. |
| The jar is corrupt or missing | Yes. |
| A plugin is misbehaving | No. Remove the plugin. |
| The server lags | No. Nothing about a reinstall makes it faster. |
| You want to start a fresh world | No. Delete the world folder instead — that is much smaller and safer. |
Doing it properly
- Take a backup and download it
A backup that only exists on the same server is not insurance against the thing you are about to do to that server.
- Set the version and type you want first
The installer uses what is in the Startup tab. Setting it after reinstalling means doing it twice.
- Reinstall and watch the console
The installer output tells you what it fetched. If it fetched the wrong version, you know before you start hunting.
- Check the jar filename afterwards
New version, new filename. This is the most common reason a server does not start after a reinstall.
If what you actually want is a fresh map, deleting the world folders and restarting regenerates them. Your plugins, configs and permissions stay exactly as they are — which is usually the point.