Fix: “Incompatible Version” Error in Borderlands 4

The error “The session you are trying to join is running an incompatible version of the game“ is a multiplayer synchronization issue that occurs when you try to start or join a co-op session.

Borderlands games use the SHiFT system to deliver hotfixes dynamically instead of relying only on full platform updates from Steam or Epic. When this process fails, the game may appear fully updated while still being version-mismatched, which prevents co-op matchmaking and joining.

One of the most common causes is corrupted or incomplete hotfix files stored in the PersistentDownloadDir folder. If the game fails to download a hotfix from SHiFT servers (sometimes getting stuck at 0%), the update never completes and the version mismatch error keeps triggering.

Before You Start: Quick Co-op Checks

Before modifying files, perform these quick checks, as the issue may be caused by the host or a pending update:

• Ensure both players fully close and relaunch the game (do not just return to the main menu).
• Have the host wait on the main menu for 30–60 seconds so SHiFT hotfixes can apply.
• Confirm all players are signed in and online (not offline or invisible).
• On console, restart the system and check for updates again.

1. Delete Cache Folder

Clearing the cache and patch folders inside PersistentDownloadDir removes corrupted or incomplete hotfix data. This forces the game to rebuild fresh hotfix files and resolves version differences between players.

1. Close the game completely (exit Steam if it is running in the tray).
2. Open Windows Explorer and navigate to:

   C:\Users\<YourUserName>\Documents\My Games\Borderlands 4\Saved

3. Open the PersistentDownloadDir folder.
4. Delete the cache and patch folders.
5. Launch the game, wait briefly at the main menu, then try co-op.

2. Unlink SHiFT Account From Steam

If the issue is caused by a corrupted authentication token or a broken account link, unlinking SHiFT forces a fresh authentication and resyncs hotfix status.

1. Visit the SHiFT official website and sign in.

2. Open Gaming Platforms.

3. Locate Steam and click Unlink.
4. Close the game if running, then relaunch and reconnect SHiFT.
5. Try joining co-op again.

3. Turn Off OneDrive Document Backup

OneDrive can sometimes move, replace, or lock files inside the Documents folder while the game is writing hotfix data. This interference can leave incomplete patch files behind, causing persistent version mismatch errors. Disabling Documents backup prevents this conflict.

Note: This does not delete files. You can re-enable backup after the issue is resolved.

1. Right-click the OneDrive icon in the system tray.
2. Open Settings.

3. Under Sync and backup, click Manage backup.

4. Turn off Documents backup.
5. Restart the game and test co-op.

4. Verify Game Files Integrity

Verifying game files replaces missing or corrupted core files. While it may not rebuild SHiFT hotfix folders directly, it can resolve underlying file corruption that contributes to synchronization and update validation issues.

1. Open Steam and go to Library.
2. Right-click Borderlands 4 and select Properties.

3. Open Installed Files and click Verify integrity of game files.

4. After verification, relaunch the game and try co-op.

5. Reinstall the Game

Reinstalling creates a completely fresh installation, removing persistent configuration or update issues that verification cannot fix. Cloud saves are usually preserved, so progress is typically safe.

Tip: Ensure cloud saves are enabled before uninstalling.

1. Open Steam and go to Library.
2. Right-click Borderlands 4 and select Manage > Uninstall.

3. Reinstall the game from Library.
4. Launch it, wait briefly at the main menu, then try co-op again.