QuickLook crashes after Windows 10 20H2 upgrade
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Description
Ever since the 20H2 upgrade, QuickLook crashes every single time I touch the space bar. I installed it from Windows Store, version 3.6.11. Also tried installing it using the msi file, still seeing exactly the same issue. I'm not 100% sure if this is related to the Windows upgrade, but could someone please let me know what I can do to have it fixed?
Edit:
Describe the bug
The crashes start after getting the Windows 10 update KB5003537 on Windows 10 20H2 and trying to preview a large JSON file(over 25MB), then QuickLook becomes unresponsive and has to be force quit. After the force quit, QuickLook will crash immediately every time no matter what file type I want to preview.
To Reproduce
Steps to reproduce the behavior:
Get the Windows 10 update KB5003537 on Windows 10 20H2
Preview a large JSON file (over 25MB) and QuickLook becomes unresponsive
Force quit QuickLook when Windows 10 prompts
Reopen QuickLook and try to preview any file, QuickLook will crash.
Expected behavior
QuickLook will keep working as normal.
Desktop (please complete the following information):
OS Version: Windows 10 Pro 20H2, OS build 19042.1081
QuickLook Version: 3.6.11 both from MS store and the msi installation package
Screenshots and Exception Log

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First steps
- Read the whole issue, then the project's contributing guide.
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- Open a pull request that references the issue number.
Research direction
Start by reproducing the crash on Windows 10 20H2 with update KB5003537, QuickLook 3.6.11, and a JSON file over 25MB; inspect the linked exception log and screenshot. Done means QuickLook remains responsive after previewing the large file, can be reopened, and previews other file types without crashing.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- csharp
- Domain
- desktop
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100