Bug: Crash on launch with SemaphoreFullException in Files.App.Program static constructor

[ShoWorld]

Description

Description

Files crashes often. I found two types of crash in the Windows Event Log (11 crashes in 14 days).

1. Crash on launch (3 processes crashed in the same second, 2026-09-18 11:37:46)
It happens when Files starts several times at the same time.

Application: Files.exe
CoreCLR Version: 10.0.1226.42308
.NET Version: 10.0.12
Description: The process was terminated due to an unhandled exception.
Exception Info: System.TypeInitializationException: The type initializer for 'Files.App.Program' threw an exception.
 ---> System.Threading.SemaphoreFullException: Adding the specified count to the semaphore would cause it to exceed its maximum count.
   at System.Threading.Semaphore.ReleaseCore(Int32 releaseCount)
   at Files.App.Program..cctor()
   --- End of inner exception stack trace ---
   at Files.App.Program.Main()

2. Native crash during normal use (2026-09-23 10:42:02)

Faulting module: ntdll.dll 10.0.26100.9444
Exception code: 0xc0000409
Fault offset: 0x000000000013dca5

Also seen: CoreMessagingXP.dll 10.0.27200.1048, exception code 0xc000027b (2 times).

Before this crash, the log shows the drive list and cloud providers reload many times. It also shows these warnings:

Warning|Invalid path: G:\My Drive
Warning|Invalid path: I:\My Drive
Warning|Value from value did not have property named mount_point_path
Warning|Invalid path: My Drive
Warning|Thumbnail load failed [...] ''; scheduling 2s timer retry.

Environment

• Files version: 4.2.9.0 (sideload, Files_4.2.9.0_x64__1y0xx7n9077q4)
• OS: Windows 11 Pro 10.0.26200
• 5 network drives (mapped), Google Drive (2 mount points), OneDrive

Steps To Reproduce

1. Set Files as the default file manager.
2. Open several folders / Files windows at the same time.
3. Files crashes on launch (crash 1, SemaphoreFullException).

Crash 2 (ntdll.dll 0xc0000409) happens randomly during normal use.

Files Version

4.2.9.0 (sideload)

Windows Version

10.0.26200.9457

User ID

No response

Log File

Files_crash.log

[hez2010]

There's a known issue about this which has been fixed in the latest branch. Can you try Files preview version to see if the issue still persists?

https://files.community/docs/getting-started/install#:~:text=Classic%20Installer

[Josh65-2201]

In future, please also

• Don't make your own categories/sections
• Don't upload part of the log file or put other text in it. You can still remove things like names, emails or parts of a path, but the log need to contains all other data.
• Make separate issues for different feedback (This includes difference crashs)