shellex.dll High CPU / Memory Leak – How to Diagnose and Fix It

Updated February 2026 — Windows 11 24H2

Your system fan is spinning constantly, Task Manager shows explorer.exe eating 15-50% CPU or 500MB+ RAM, and Windows feels sluggish even when you are not doing anything. The most common cause? A shell extension DLL with a bug that causes infinite loops, memory leaks, or excessive disk/network activity.

This guide walks you through diagnosing exactly which DLL is the culprit and fixing it permanently.

Understanding the Problem

Shell extensions run inside the explorer.exe process. When you see high CPU or memory usage for explorer.exe, it is not Explorer itself that is broken — it is one of the dozens of third-party DLLs loaded into it.

Common Culprits

How Memory Leaks Happen

A memory leak occurs when a DLL allocates memory (e.g., for rendering an icon or scanning a file) but never releases it. Over hours or days of use:

1. Explorer opens a folder → Extension allocates 2MB for icon rendering.
2. Explorer closes the folder → Extension does not release the 2MB.
3. Repeat 1000 times → Explorer is now using 2GB of RAM.
4. Windows starts swapping to disk → entire system becomes sluggish.

Step 1: Confirm Explorer Is the Problem

Open Task Manager (Ctrl+Shift+Esc) and check:

1. Click the Details tab.
2. Find explorer.exe.
3. Note the CPU and Memory columns.
4. Normal baseline: CPU < 1%, Memory 80-150MB.
5. Abnormal: CPU > 5% sustained, or Memory > 300MB and growing.

Quick Test: Restart Explorer

# Kill and restart Explorer
Stop-Process -Name explorer -Force
Start-Sleep 2
Start-Process explorer

If memory usage drops from 500MB back to 100MB after restart — you have a memory leak. If CPU drops from 20% to 0% — you have a CPU-hogging extension.

Step 2: Identify the DLL with Process Monitor

Process Monitor (Sysinternals) is the gold standard for tracing which DLL is consuming resources:

1. Download from Sysinternals.
2. Run as Administrator.
3. Set these filters:
   • Process Name is explorer.exe
   • Operation is Thread Create or Load Image
4. Let it capture for 30-60 seconds.
5. Look for DLLs that trigger repeated Thread Create events — these are likely spinning up work threads in a loop.

What to Look For

• Repeated ReadFile operations on the same file → possible infinite scan loop.
• Repeated TCP Connect events → extension trying to reach a dead server.
• Hundreds of RegQueryValue events per second → polling registry excessively.

Step 3: Use Performance Monitor for Memory Leaks

Windows Performance Monitor can chart memory growth over time:

1. Press Win + R, type perfmon, press Enter.
2. Click Performance Monitor on the left.
3. Click the green + button to add counters.
4. Select Process → Private Bytes → explorer.exe.
5. Let it run for 30-60 minutes.
6. If the line trends steadily upward without plateauing — you have a memory leak.

PowerShell: Monitor Memory in Real-Time

while ($true) {
    $proc = Get-Process explorer -ErrorAction SilentlyContinue
    if ($proc) {
        $mb = [math]::Round($proc.WorkingSet64 / 1MB, 1)
        $cpu = $proc.CPU
        Write-Host "$(Get-Date -Format 'HH:mm:ss') | RAM: ${mb}MB | CPU Time: ${cpu}s"
    }
    Start-Sleep 10
}

Run this for 10-15 minutes. If RAM grows by more than 50MB with no user activity, a shell extension is leaking memory.

Step 4: Isolate the Extension with ShellExView

Once you have confirmed the issue:

1. Open ShellExView as Administrator.
2. Disable all non-Microsoft extensions (F7).
3. Restart Explorer.
4. Monitor CPU and memory for 5 minutes.
5. If the problem stops — re-enable extensions in groups of 5.
6. After each group, monitor for 5 minutes.
7. When the problem returns — the culprit is in the last group of 5.
8. Narrow down within that group one by one.

Known High-CPU Extensions (2026)

Based on community reports, these extensions frequently cause high CPU:

• Adobe Creative Cloud (CCXProcess.dll)
• Kaspersky context menu scanner
• Nahimic audio overlay (NahimicOSD.dll)
• Intel Graphics context menu (igfxDTCM.dll)
• Outdated NVIDIA shell extensions
• Corrupted OneDrive overlay handlers

Step 5: Fix the Problem

Option A: Update the Software

Check if the software vendor has released a patch. Memory leaks are common bugs that get fixed in updates.

Option B: Disable the Extension Permanently

If you do not need the context menu integration:

1. Leave it disabled in ShellExView.
2. The parent app continues to work.

Option C: Registry Cleanup for Orphaned Extensions

Find and remove extensions pointing to non-existent DLLs:

$paths = @(
    "Registry::HKCR\*\shellex\ContextMenuHandlers",
    "Registry::HKCR\Directory\shellex\ContextMenuHandlers",
    "Registry::HKCR\Folder\shellex\ContextMenuHandlers"
)

foreach ($regPath in $paths) {
    Get-ChildItem $regPath -ErrorAction SilentlyContinue | ForEach-Object {
        $clsid = $_.GetValue("")
        if (!$clsid) { return }
        $inproc = "Registry::HKCR\CLSID\$clsid\InprocServer32"
        if (!(Test-Path $inproc)) { return }
        $dll = (Get-ItemProperty $inproc -ErrorAction SilentlyContinue)."(default)"
        if ($dll -and !(Test-Path $dll)) {
            Write-Host "ORPHANED: $($_.PSChildName) -> $dll" -ForegroundColor Red
        }
    }
}

Option D: Use Revo Uninstaller for Complete Cleanup

If the culprit belongs to software you want to remove entirely, use Revo Uninstaller Pro to remove the application AND all its leftover registry entries, temporary files, and shell extension registrations.

Frequently Asked Questions

Q: Can a memory leak cause a Blue Screen? A: Unlikely but possible. If explorer.exe consumes all available RAM, other system processes may crash, potentially causing a BSOD with RESOURCE_NOT_OWNED or POOL_CORRUPTION stop codes.

Q: Does restarting Explorer fix the leak permanently? A: No — it only resets the memory usage temporarily. The leak will resume as the extension continues to run. You need to disable or update the offending extension.

Q: Why does CPU usage spike when I open certain folders? A: Thumbnail providers and preview handlers activate when viewing files. If one of these extensions has a bug, it can spike CPU every time you open a folder with those file types.

Q: Is it safe to kill explorer.exe? A: Yes. Killing explorer.exe temporarily removes your taskbar and desktop icons. It restarts automatically or you can start it manually from Task Manager → File → Run new task → explorer.exe.