Direct answer: There is no approved universal fix for a How to Fish co-op black screen or failed join. The safest order is to confirm matching builds, save explicitly, recreate a fresh lobby, test Steam invite and server-ID joining separately, restart both clients if the room is stale, and then report the exact host/client conditions if the failure persists.
Version boundary: Reviewed through the latest visible official Patch 1.0.8 on 2026-08-24. Player reports after the hopeful Patch 1.0.4 fix remain unresolved.
Low-risk diagnostic order
| Step | Action | What it helps distinguish |
|---|---|---|
| 1 | Compare the visible game version on host and client | A simple build mismatch |
| 2 | Use the explicit Save action before changing the room | Session troubleshooting from avoidable progress risk |
| 3 | Create a fresh lobby | A stale long-running room from a repeatable join failure |
| 4 | Test a Steam invite and the server-ID path separately | One join path from a general connection symptom |
| 5 | Restart both clients, then create another fresh room | Client/session state from a persistent account or network issue |
| 6 | Record the exact black, gray, frozen, or no-response symptom | Different failures that should not be collapsed into one report |
The official Steam patch feed says Patch 1.0.4 hopefully fixed black- and gray-screen issues. That wording is not a guarantee. A Steam community thread records mixed launch-period reports: recreating or restarting helped some players, but not everyone.
Stale or fake server entries
Patch 1.0.6 added save validation before loading to avoid fake “Game Name” server entries. If you see that symptom on a build that should include the patch, capture the version and room list state. Do not assume the remaining entry has the same root cause as a join black screen.
What to include in a useful report
Copy this checklist into your notes:
- host game version and client game version;
- host and client operating system version;
- public or invite-only session type;
- whether Steam invite, server ID, or both failed;
- whether the lobby was fresh or had been running for a long time;
- exact symptom: black screen, gray screen, frozen loading, no response, disconnect, or fake room name;
- whether both clients restarted and whether a fresh room changed the result;
- whether the issue happens with another host/client pairing.
This information narrows reproduction without claiming a cause that the approved sources do not establish.
Avoid destructive guesses
The dossier does not establish a specific firewall rule, port, antivirus exception, save-file path, cache deletion, host migration rule, or network root cause. Do not delete saves, disable security software, open broad ports, or promise that reinstalling will fix the issue based on these sources.
If both join paths fail after a fresh room and matched builds, preserve the data you collected and escalate it through the game's current official support or community channel. Community discussion titles establish that players have reported the problem; they do not turn any single workaround into a guaranteed remedy.