Forum Discussion

alexspecht's avatar
alexspecht
Brass Contributor
Jul 21, 2026

Explorer crash - ucrtbase.dll

Haven't seen this happen in a while.

Every once in a while explorer crashes, then comes back on.  So far no one has gotten injured, but it is annoying.

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NOTE: Please DO NOT post genaric suggestions such as

  • run DISM (Deployment Image Servicing and Management)

  • run Check Disk (CHKDSK)

  • Make sure drivers are up to date
  • etc...

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I am posting the log below.  If anyone has an idea what might cause this please post, thanks in advance:

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Faulting application name: sihost.exe, version: 10.0.26100.8328, time stamp: 0x15de642d

Faulting module name: ucrtbase.dll, version: 10.0.26100.8875, time stamp: 0x303b538a

Exception code: 0xc0000409

Fault offset: 0x00000000000a527e

Faulting process id: 0xFC8

Faulting application start time: 0x1DD194880CC39EF

Faulting application path: C:\WINDOWS\system32\sihost.exe

Faulting module path: C:\WINDOWS\System32\ucrtbase.dll

Report Id: 5a13a22b-712b-4d57-b396-9f24f69c1843

Faulting package full name:

Faulting package-relative application ID:

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System Info

Lenovo Laptop

Processor 11th Gen Intel(R) Core(TM) i3-1115G4 @ 3.00GHz (3.00 GHz)

Installed RAM 8.00 GB (7.79 GB usable)

Graphics card Intel(R) UHD Graphics (128 MB)

Storage 135 GB of 238 GB used

Device ID 86E9A61B-7099-4C7A-8470-CF4FA9CCBA17

Product ID 00356-07357-63666-AAOEM

System type 64-bit operating system, x64-based processor

 

Application Management
device management

3 Replies

  • CameronLewis's avatar
    CameronLewis
    Iron Contributor
    Jul 27, 2026

    Faulty RAM can cause unpredictable crashes, especially if buffer overflows are involved.

  • Jamony's avatar
    Jamony
    MCT
    Jul 21, 2026

    The event shows that sihost.exe, rather than File Explorer itself, terminated while calling ucrtbase.dll with exception 0xc0000409. That identifies the crash location, but it does not prove ucrtbase.dll is the root cause. System-file corruption or a background software conflict still needs to be tested. Since DISM and CHKDSK have already completed, install all Windows updates, including any offered Lenovo driver updates, restart, then run an elevated Command Prompt and execute sfc /scannow. Note whether SFC repairs anything. If the crash returns, perform a clean boot by hiding Microsoft services, disabling the remaining services and startup apps, and testing normally. Re-enable items in groups to isolate the conflict. If it still crashes in a clean boot, press Win+F after the next occurrence and submit Feedback Hub diagnostics with the Event Viewer entry and report ID. Avoid replacing ucrtbase.dll manually; use Get Help or Microsoft Support if SFC cannot repair files.

    • alexspecht's avatar
      alexspecht
      Brass Contributor
      Jul 23, 2026

      This is exactly the type of response that I specifically mentioned:

      NOTE: Please DO NOT post genaric suggestions such as

      • run DISM (Deployment Image Servicing and Management)
      • run Check Disk (CHKDSK)
      • Make sure drivers are up to date
      • etc...
      • add to the list Feedback Hub diagnostic,s Get Help, or Microsoft Support

       

      These types of responses are NEVER helpfull. 

       

      The question is WHAT would cause this type of crash.  sihost.exe is effectively explorer in this case.  Explorer goes blank and comes back, for no reason.