Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

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Latest checklists

You try to push your local commits to a remote Git repository, but Git refuses with: ! [rej...

Fix 'Git Remote Origin Already Exists' Error
When you try to add a remote named 'origin' but Git tells you it already exists, it's...

Fix Git 'index.lock file exists' Error
When you see the error fatal: Unable to create 'path/.git/index.lock': File exists....

Fixing Nginx Upstream Connection Refused and Permission Denied
If you see connect() failed (111: Connection refused) or connect() failed (13:...

Fix Git 'index.lock' File Exists Error in SourceTree
If you use SourceTree and see an error message like fatal: Unable to create 'path/to/.g...

Fix Python Dependency Conflicts After an Update
You updated your Python environment or a package, and now your script throws import errors or ver...