Failed to Load il2cpp on Windows 11: Fix Loop Dungeon Incremental

What error do Windows 11 players see?

Playsect’s launch-day Steam announcement states that some Windows 11 players crash at startup with Fatal error: Failed to load il2cpp. That message appears before normal gameplay loads. If you see a different crash, treat it as a separate issue—see system requirements for platform support and patch notes for post-launch fixes.

Why does Smart App Control block the game?

In [IMPORTANT] Windows 11 Smart App Control Issue (Failed to load il2cpp) (2026-10-19), Playsect ties the crash to Windows 11 Smart App Control (SAC) and Unity’s IL2CPP backend. The game depends on GameAssembly.dll. Because the build was not yet code-signed, SAC treated that DLL as untrusted and blocked it from loading, which triggers the il2cpp fatal error.

Microsoft’s Smart App Control FAQ describes a similar rule: if the cloud service cannot confidently predict an app is safe, SAC checks for a valid signature; unsigned or invalidly signed apps can be considered untrusted and blocked. Microsoft documents the same general rule; this page asserts no Windows behavior beyond what Microsoft publishes.

What are Playsect’s official temporary fixes?

Try these in order, exactly as written in the developer announcement—do not add extra registry edits or downloaded “DLL fixes” from unofficial sites.

Method 1: Unblock all game files (most effective)

1. In your Steam Library, right-click Loop Dungeon - Incremental → Manage → Browse local files.
2. In the install folder, press Ctrl+A to select all files.
3. Right-click any selected file → Properties.
4. On the General tab, check Unblock.
5. Click Apply, then OK.
6. Restart the game.

This addresses the Mark of the Web on files downloaded from the internet—the same “Unblock” control Windows documents for files copied from the web.

Method 2: Update Windows Security intelligence

1. Open Windows Security.
2. Go to Virus & threat protection.
3. Under virus and threat protection updates, click Check for updates.
4. Restart your PC and launch the game again.

What permanent fix did Playsect promise on 2026-10-19?

In the same announcement, Playsect said they were:

• Obtaining a code signing certificate for the game executable and DLLs.
• Updating Unity engine dependencies for better compatibility with Windows security features.

As of verification date 2026-10-20: we have not confirmed from a later official post that a fully signed build is available on Steam. Watch patch notes after you install updates.

What if the game still will not start?

If both methods fail, gather:

• Your Windows 11 version (Settings → System → About).
• A screenshot of the Failed to load il2cpp message.
• Which steps you already tried.

Report through official channels only:

• Steam Community discussions for app 4621970
• Official Discord: https://discord.gg/KWeEwYytaD

Related reading: demo save transfer if you are migrating from the Steam Demo, and the guides hub for other launch-week topics.

Still crashing after the official fixes?

Playsect also replied in the Steam thread Full game crashes when opening—that OP describes crashes when opening, not necessarily the Failed to load il2cpp string from the SAC announcement. We do not infer those threads share one root cause.

Playsect’s wording (verbatim):

• Please join discord or email me, I'll make special version for you to solve the problem — 19 Oct 2026 @ 5:30:40 am PDT
• Contact me, I am solving it. — 19 Oct 2026 @ 6:14:17 am PDT

That pattern suggests case-by-case builds for some launch crashes, not a blanket “all players fixed” statement. For contact paths we publish on this wiki, use the contact options on the game’s Steam page: https://store.steampowered.com/app/4621970/ (we do not list personal email addresses here).

Broader reply inventory: developer replies.

Sources and verification

Official = Steam store, news, screenshots and statistics · Developer = Playsect’s own replies · Player reports = reviews and discussions, treated as anecdotes.

Not verified on this date: whether a code-signed Steam build has shipped; whether Windows 10 shows the same crash pattern; whether “special version” builds apply to il2cpp/SAC cases; any unofficial workaround beyond the announcement.