'COM Surrogate has stopped working' error appears repeatedly

Symptoms

• Error specifically names COM Surrogate (dllhost.exe)
• Often happens while browsing a folder with images, videos, or certain document types
• May repeat several times if you keep browsing the same folder
• Rest of the system continues working around these crashes

Likely causes

• CommonCorrupted thumbnail generation for a specific fileCOM Surrogate often handles generating file previews, and a single damaged file can repeatedly crash this process.
• CommonOutdated or faulty codec (for video/audio file previews)A bad codec used to generate video thumbnails is a frequent specific cause.
• PossibleCorrupted thumbnail cacheBeyond a single bad file, a broadly corrupted cache can cause repeated crashes across many files.
• Less commonMalware disguising itself using this legitimate process nameGenuine malware rarely uses this exact process, but it's worth ruling out if crashes are unusually frequent or severe.

What to do

1. Note which specific folder or file type you were browsing when the crash occurred, since a single problematic file is often the trigger.
2. Switch File Explorer to a view that doesn't generate thumbnails (View > choose 'Details' or 'List' instead of Large/Medium icons) temporarily to confirm this stops the crashes.
3. If switching views stops the crashes, try to identify and remove or move the specific file that's problematic by testing a few at a time.
4. Clear the thumbnail cache via Disk Cleanup (check 'Thumbnails' specifically) and restart the computer.
5. Update or reinstall any third-party video/audio codec packs you have installed, since outdated codecs are a common specific cause.
6. Run a malware scan as a general precaution, especially if crashes are accompanied by other unusual behavior.
7. If crashes continue broadly across many unrelated files and views, run 'sfc /scannow' to check for underlying system file corruption.

When to call a pro

If a specific file keeps crashing COM Surrogate and you need its contents, a technician can help extract or convert it safely without relying on thumbnail generation.

Safety