Start here for any problem, because the first step is the same for all of them: open the Logs page. If the game exited, the crash is already captured — even when it died before Minecraft opened its own log — and the analysis names the mods most likely responsible.
The game closes immediately
Open Logs, press Analyse. Two common shapes:
# A mod built for a different Minecraft version java.lang.NoSuchMethodError: net.minecraft.client.gui.GuiGraphics.fill(IIIIII)V at com.example.mymod.MyMod.onRender(MyMod.java:112) # Fix: disable the named mod, or install the build for this version. # Not enough memory, or too much asked for java.lang.OutOfMemoryError: Java heap space # Fix: Settings → Java, raise the maximum, do not exceed your physical RAM.
If several mods are implicated and you want a clean answer, press Disable all mods on the Logs page and launch. If it works, re-enable in halves until it breaks — which is a binary search, and much faster than guessing.
Black screen, or a window that never appears
- Check the version's Java requirement. A runtime that is too old gives an
UnsupportedClassVersionErrorand a window that never draws. - Try a clean options file. A corrupt
options.txtin the instance's folder can produce a window that opens at zero size. Rename it and let the game write a new one. - Turn off shaders. A shaderpack that does not match your GPU driver can hang on the loading screen. Remove the shaderpack folder's contents and launch again.
Sign-in problems
| What you see | What it means |
|---|---|
| "The session ID saved for you has expired" | The pasted token is a day old. Get a fresh one from the launcher it came from and add the account again. |
| "Microsoft rejected the stored token" | The refresh token was revoked — usually a password change or a security reset. Sign in again. |
| "Mojang is rate-limiting" | Too many attempts. Wait a minute. Nothing is broken. |
| "Invalid session" in game | Minecraft launched with a dead token. The launcher checks before handing it over, so this means the token died between the check and the launch. Sign in again. |
Downloads that will not finish
- Settings → Storage → Clear caches. This removes cached metadata, not game files.
- Install the version again. Completed files are kept, so this resumes rather than restarting.
- If one file repeatedly fails its checksum, something between you and the internet is rewriting responses. A proxy, a filter or an antivirus with HTTPS inspection is the usual cause; exclude the launcher's data folder and try again.
The launcher itself will not start
- Nothing happens at all — check Task Manager for a lingering
DonutLauncher.exeand end it, then start again. The updater cannot replace a running executable, which is also what a failed update looks like. - A white window — the renderer failed to load. Run the installer again over the top; it repairs a partial install without touching your settings.
- It starts and immediately exits — start it once from a terminal to see the error text, or check
%APPDATA%\DonutLauncher\logs\launcher.log, which is written before the window is created.
Resetting without losing anything
Server addresses, scan history, accepted terms and download caches are safe to delete individually. Settings → Storage lists each with its size and a clear action. Nothing in that list touches your accounts or your worlds.
Reporting a bug well
Settings → About has Write diagnostics report. It writes a file containing system information, the channel list and the tail of the launcher log. Attach that with a sentence about what you did and what happened instead — that is a bug report somebody can act on, and it never includes your account or your worlds.