You updated ReHLDS or ReGameDLL, and now the server crashes on startup or refuses to load the game DLL. ReHLDS (the engine) and ReGameDLL_CS (the game logic) talk over a versioned interface, and when the two builds expect different versions of that interface the game library is rejected or the process segfaults during initialization. This is a compatibility problem, not corruption, and the fix is to get both onto a matched set. Here is how to diagnose and do that.
1. Read the startup banner
Both projects print their version to the console at boot. Start the server from a terminal (not detached) so you can see the lines before the crash:
./hlds_run -game cstrike -console +map de_dust2
ReHLDS prints its engine version early; ReGameDLL prints its own banner as the game DLL initializes. If the crash happens after the ReHLDS line but before or during the ReGameDLL line, the game DLL is failing to attach to the engine — the signature of a version mismatch. Note both version strings; you need them to pick a compatible pair.
2. Recognize the mismatch errors
The console around the crash usually names the interface. Common lines include a failure to load the game library or an API version complaint:
Failed to load the "cs" game DLL Game DLL version mismatch
A hard segfault with no message right as the game DLL loads is the same class of problem — the DLL called into an engine ABI that changed. Either way the meaning is: this ReGameDLL build was compiled against a different ReHLDS API than the one you are running.
3. Match the pair, do not mix eras
The reliable fix is to run ReHLDS and ReGameDLL builds from the same release window. Do not pair a brand-new ReGameDLL with a ReHLDS from two years ago, or vice versa. Decide which one you actually needed to update and bring the other forward to match. Update both binaries together:
- The ReHLDS engine binaries (
engine_i486.so/ the swds library) go in the HLDS root. - The ReGameDLL game library (
cs.so/mp.dll) goes incstrike/dlls/.
Replace both, keeping backups of the old files, then boot. A matched pair passes the handshake and the ReGameDLL banner appears cleanly. This is the base install described in the ReGameDLL guide.
4. Keep Metamod and ReAPI in step
If you run Metamod-r and the reapi module, they sit in the same dependency chain. A ReGameDLL update that changes hook chains can break an old reapi module, producing bad load or a later crash even after the engine handshake succeeds. When you move ReHLDS and ReGameDLL, refresh the reapi module too, and confirm Metamod-r is a build that supports your ReHLDS. See the ReAPI native fix for how that layer reports failure.
5. Roll back cleanly if the update was the trigger
If the crash started the moment you updated one component and you cannot immediately source a matching build, restore the backups you took and return to the last-known-good matched set. This is why keeping the previous cs.so and engine files before any update matters — a mismatch is instantly reversible if you kept the old pair. Never update one of the two in isolation on a live server without the other's matching build ready.
Troubleshooting
Failed to load the "cs" game DLL— the game library is the wrong architecture or built against a different engine API. Replace it with a build matching your ReHLDS.- Segfault right as the game DLL loads, no message — ABI mismatch between ReGameDLL and ReHLDS. Match the pair (step 3).
- ReHLDS banner prints, then instant exit — ReGameDLL rejected the engine version. Update ReGameDLL to the same era.
- Boots but reapi plugins are
bad load— the reapi module is out of step with the new ReGameDLL. Update the module. - Crash returned after a working period — an automated update pulled one component forward. Pin versions and update both together.
- Works with stock game DLL, crashes with ReGameDLL — confirms the game DLL is the mismatched piece, not the engine.
Verification
Boot the server in a terminal and confirm both banners print in sequence — the ReHLDS engine line, then the ReGameDLL version line — with no crash between them and the map loading normally. Connect a client and confirm gameplay logic (buy menu, round timing, ReGameDLL-specific cvars) behaves. If both banners appear and the map loads, the handshake succeeded and the versions are compatible; save that exact pair of binaries as your known-good baseline before the next update. Then re-check any ReAPI plugins load, since they depend on the same matched stack.
