Hi everyone! I'm not sure I'm posting in the right forum thread.
I'm playing Jazz 2, which I bought from GOG. There's an error on the Gargoyles Lair level that prevents me from completing the level and advancing to the next one. Editing the level file in JSC didn't help. Any tips on how to get around this other than replaying from an earlier save?

I understand that the error may be related to the native Jazz 2, but I play Jazz 2 Plus... What's why I wrote it here...

Hello! Can you be more specific about what error you're talking about? I can beat Gargoyle's Lair just fine. There used to be a problem where beating Gargoyle's Lair would return you to Gargoyle's Lair again, infinitely, but that's been fixed in Jazz 2 Plus since August 2020.

Originally Posted by Violet CLM

Hello! Can you be more specific about what error you're talking about? I can beat Gargoyle's Lair just fine. There used to be a problem where beating Gargoyle's Lair would return you to Gargoyle's Lair again, infinitely, but that's been fixed in Jazz 2 Plus since August 2020.

I got a map not found error after completing a level, and it just kicked me back to the main menu.
My JJ2+ version is v6.6a.
I was playing as Lori, if this is a specific error.

I finished the game using old save for two levels earlier. And when deleted the game.
And now for testing I have a strange thing. After reinstalling and patching - its worked now. But for test I use jjnext to medieval to test secret level and exit.
Old save with this bug is lost...
At the time when the bug occurred, I went through the entire campaign, moving from episode to episode.
Question: I started playing on a version that was before January 10th and encountered a bug. Then the game updated, but the bug persisted. But after reinstalling, everything was fixed. Could this mean the save file remembers the version it was originally saved on?
The original version I encountered the bug on was January 6th, if I not wrong about it.

Maybe you deleted Medivo2.j2l by mistake, and then reinstalling recreated that level file? It's hard to be sure if

I got a map not found error

you don't know which map was not found.

I checked, all the levels were there. I checked the level properties in the level editor to see which one led where to try to work around the problem, but it didn't help.
It turns out I didn't get a response on the forum that day (I'm not blaming anyone) and replayed some of the levels.
I usually use two or three save slots as backups. Because cases of player characters getting stuck in level structures still occur.
I had a save file when I had already reached Gargoyles Lair, and there was an older save file on the first level of the Tube Electric scene. (Don't remember the right name of the map).
When I got the file not found error, I started playing from the second save, reached Medivo 1, skipped the secret level, and simply completed it and moved on to Medivo 2. I finished the entire game that same day, so I had no further problems. After replaying, I uninstalled and reinstalled the game.
I saw your message a few days later and decided to test it. And everything worked. However, during the test, I simply "jjnext" into Medivo1 using the code, reached the secret, and completed it, returning to Medivo1 to the location of the secret level entrance.
When I first played and discovered the problem, I started from the very beginning of the Secret Files episode, advancing through the game from episode to episode. Who knows? Perhaps the bug was in the save file itself.
But I can try playing through the entire game again, attempting to access this secret level, and if the error persists, I'll take a screenshot.

I reproduced this issue.
Full description in text: Error loading level - No next (level) selected in file.
Press Fire to continue. After that, it takes you to the menu.
I couldn't insert a screenshot here.

Now I'll describe it step by step.
I play Jazz 2 through GOG Galaxy.
When I do a clean install of the game (delete it completly and install over), it asks to update to the latest version, which is currently 6.6a, dated January 10, 2026. Everything works fine with this build: I've played from the very beginning to the secret level and beyond.
Then I made a save before exiting the Gargoyles Lair level for testing.
Then I checked the cache through GOG Galaxy, and it redownloaded the old files, just like before the update?version 6.3, from September 2, 2025. After the first launch, the game again asked me to update to version 6.6a, and after that, the level Gargoyles Lair crashed on exit. The all files were still there. But something wrong.
It turns out that verifying the game's integrity through GOG Galaxy breaks some files. Now, to restore functionality, I have to completely delete all files except the saves, install the game from scratch, update, and never verify the game's integrity again.
The problem is that the GOG Galaxy client periodically runs an integrity check on installed game files. The day before I wrote this post, Jazz2 ran through an integrity check. That's why I couldn't exit the level. That's how it works.

I double-checked everything. All my steps turned out to be incorrect. And the problem is actually less complex, but hard to check it: if I save game on the Gargoyles Lair level, then simply exit the game, re-enter, and try to resume from the save, the problem returns.
So, if you play through all the levels from Mediva group in one go, everything works. But if you save in a secret level, finish the game, and then restart from the saved game in the secret level, you won't be able to complete it.

The only way to get around this problem is to have a save at Mediva1 map before entering the secret.
Then it's possible to go to secret level, completed it, return to Mediva1 and complete it, and go to Mediva2 map. Whats all.

Aha. Entering a secret level in the Gargoyle's Lair style creates a file (either SAVEGAME.666 or SAVEGAME.123 depending on game version) which is a save file from the level you entered, here Medieval Kineval. Then when you exit the secret level, JJ2 reloads that save file. I could certainly imagine the game getting confused if you create a manual save (SAVEGAME.000 for example) in the secret level, exit the game, and do any number of other things, before eventually reloading it.

The only way I'm currently thinking of that the game could address this would be to include the contents of SAVEGAME.666/123 inside SAVEGAME.000, so it's clear which level to return to. Otherwise if you created a save in Gargoyle's Lair, then created a save in some other secret level, then reloaded your Gargoyle's Lair save, it would exit you back into whichever level led to that other secret level that you had visited more recently.

Originally Posted by Violet CLM

Aha. Entering a secret level in the Gargoyle's Lair style creates a file (either SAVEGAME.666 or SAVEGAME.123 depending on game version) which is a save file from the level you entered, here Medieval Kineval. Then when you exit the secret level, JJ2 reloads that save file. I could certainly imagine the game getting confused if you create a manual save (SAVEGAME.000 for example) in the secret level, exit the game, and do any number of other things, before eventually reloading it.

The only way I'm currently thinking of that the game could address this would be to include the contents of SAVEGAME.666/123 inside SAVEGAME.000, so it's clear which level to return to. Otherwise if you created a save in Gargoyle's Lair, then created a save in some other secret level, then reloaded your Gargoyle's Lair save, it would exit you back into whichever level led to that other secret level that you had visited more recently.

Or maybe it can be done like this - when you in the secret level - you can't save at all. And you must go thru entire level to return back. It's not vanila option, but hardered gameplay in some ways.
And not broke the game.

I guess that might be a necessary stopgap for now, but I'm confused why this would be working differently in vanilla and JJ2+, it doesn't seem like there's an obvious reason that would need to broken right now...