COM Surrogate (dllhost.exe) memory leak and high CPU during video browsing
The Windows COM Surrogate process crashes or leaks gigabytes of when attempting to generate thumbnails for corrupt video files, MKV codecs, or damaged image directories.
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Common Symptoms & Tells
- dllhost.exe accumulates several gigabytes of in Task Manager
- File Explorer freezes when opening the Downloads or Videos folder
- Video thumbnails show blank white icons or freeze the green loading bar
Interactive Fix Checklist
0 of 4 steps completedClear and rebuild the Windows thumbnail cache
Press Win + R, type 'cleanmgr', select drive C:, check only 'Thumbnails', and click OK to purge the corrupted thumbnail database.
Update or install the K-Lite Codec Pack
Corrupted MKV or MP4 thumbnail handlers leak memory in dllhost.exe. Installing the standard K-Lite Codec Pack or Icaros Thumbnailer replaces faulty shell extension decoders.
Toggle File Explorer to show icons instead of thumbnails
In File Explorer, click the 3 dots (...) > Options > View tab > Check 'Always show icons, never thumbnails' > Click Apply to isolate thumbnail extraction as the root cause.
Scan storage for corrupt media files
Locate newly downloaded video files in the affected directory and move them to an isolated folder to determine which specific corrupt file triggers the COM Surrogate crash.
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