# Suggested title

Crash during startup autosave after loading a Survival world - InvalidOperationException in MountPathResolver.PathIsUnderMount (2.4.0.95)

# Bug description

Space Engineers 2 crashed to the desktop immediately after loading a Survival world, when the automatic startup save began. The standard "Application has crashed" dialog appeared and directed me to the log.

The attached main log shows that the world finished loading at 16:25:37.413 and requested a startup autosave. The fallback save then failed at 16:25:38.051 with:

`System.InvalidOperationException: Collection was modified; enumeration operation may not execute.`

The first relevant stack frames are:

`Keen.VRage.Library.Filesystem.MountPathResolver.PathIsUnderMount`

`Keen.VRage.Library.Filesystem.RootFileSystem.VerifyPathNotMounted`

`Keen.VRage.Library.Filesystem.FileContainerAdapter.StoreBlobs`

`Keen.Game2.Simulation.RuntimeSystems.Serialization.EntityContainerSerializer.Serialize`

`Keen.Game2.Simulation.RuntimeSystems.Saves.SaveSessionComponent.RunAutosave`

# Steps to reproduce

1. Start Space Engineers 2 normally through Steam.
2. Open Load Game.
3. Load the Survival world named `Исследовательский центр «Конкордия»` (Research Center "Concordia").
4. Wait for the world to finish loading and for the startup autosave to begin.
5. The save fails and the game closes with the crash dialog.

# Reproducibility

I have experienced several unexpected game closures while using this save. The attached logs confirm the autosave exception for the occurrence on 2026-09-04 at approximately 16:25 local time. I have not yet confirmed that every earlier crash had the same exception.

# Expected result

The world loads and the automatic save completes without closing the game.

# Actual result

The world loads, startup autosave starts, the save fails with `InvalidOperationException`, and the game terminates.

# Environment

- Game version: 2.4.0.95
- OS reported by the game: Microsoft Windows 10.0.26200
- CPU: AMD Ryzen 5 7500F, 6 physical / 12 logical cores
- RAM: 32 GB
- GPU: NVIDIA GeForce RTX 3080 Ti
- NVIDIA driver reported by NvAPI: 610.88 (`r610_85`)
- Resolution: 2560 x 1440, fullscreen, VSync enabled
- Graphics preset: High
- Ray tracing: Medium
- Game installed on SSD

# Mod status

The game discovered a local development mod folder named `VCS LCD Pack` during startup, but the loaded world line contains an empty mod list: `mods:`. The log does not show the mod project being mounted for this session. Therefore, the crash occurred in a world session with no active mods.

# Additional observations

- The render log does not contain a GPU device-removed error or an out-of-memory exception at the time of the crash.
- The render log contains texture-streaming pressure reports and missing vanilla SPERA material resources. These may be separate content/rendering issues, but the fatal exception recorded in the main log occurred in the autosave/file-system path.
- The first attempted autosave target returned `FailureNoLocalSave`; the fallback save for `Исследовательский центр «Конкордия» 1` then failed with the exception above.

# Attachments

- `SpaceEngineers2_260904_162504_501_7396.log` - main game log with the fatal exception and full stack trace
- `SpaceEngineers2_260904_162504_501_7396_Render12.log` - render log from the same session
- `Crash_screenshot_2026-09-04_162547.png` - screenshot of the crash dialog immediately after world load

I can provide the affected world save as an additional attachment if required.