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Windows Security blocks OpenTUI DLL during opencode initialization: Error Code 4551 #21234
Description
Description
When running opencode on Windows, the application fails to start because Windows Security blocks a temporary DLL used by the OpenTUI render library.
I ran opencode --print-logs and got the following:
INFO 2026-04-06T20:04:02 +588ms service=default version=1.3.17 args=["--print-logs"] opencode
INFO 2026-04-06T20:04:02 +12ms service=default directory=C:\Users\[USER]\OneDrive\Desktop\[PROJECT_PATH]
INFO 2026-04-06T20:04:02 +12ms service=project directory=C:\Users\[USER]\OneDrive\Desktop\[PROJECT_PATH] fromDirectory
INFO 2026-04-06T20:04:02 +29ms service=db path=C:\Users\[USER]\.local\share\opencode\opencode.db opening database
INFO 2026-04-06T20:04:02 +11ms service=db count=10 mode=bundled applying migrations
INFO 2026-04-06T20:04:02 +33ms service=config path=C:\Users\[USER]\.config\opencode\config.json loading
INFO 2026-04-06T20:04:02 +1ms service=config path=C:\Users\[USER]\.config\opencode\opencode.json loading
INFO 2026-04-06T20:04:02 +9ms service=config path=C:\Users\[USER]\.config\opencode\opencode.jsonc loading
ERROR 2026-04-06T20:04:02 +150ms service=default e=Failed to initialize OpenTUI render library: Failed to open library "C:\Users\[USER]\AppData\Local\Temp\.d9ffdfa87bffbbfc-00000001.dll": error code 4551 rejection
ERROR 2026-04-06T20:04:02 +0ms service=default Error: Failed to initialize OpenTUI render library: Failed to open library "C:\Users\[USER]\AppData\Local\Temp\.d9ffdfa87bffbbfc-00000001.dll": error code 4551
I have tried clearing the cache from the .cache directory but it hasn't resolved the issue.
Plugins
openducky@latest
OpenCode version
1.3.17
Steps to reproduce
- Open Terminal
- Run
opencode
Screenshot and/or share link
Operating System
Windows 11
Terminal
Windows Terminal
Activity
github-actions commentedon Apr 6, 2026
This issue might be a duplicate of existing issues. Please check:
Trojan:Win32/Wacatac.H!mlwhen running opencode #7592: Windows Defender detects Trojan when running opencode (false positive discussion)These issues cover the same root cause: Windows Defender/antivirus blocking the temporary DLL file that opencode extracts at runtime. Please review those threads for any existing workarounds or fixes before continuing here.
[-]Windows Defender blocks OpenTUI DLL during opencode initialization: Error Code 4551[/-][+]Windows Security blocks OpenTUI DLL during opencode initialization: Error Code 4551[/+]thePrnvBot commentedon Apr 7, 2026
The issue appears to have sorted itself, since I filed this issue.