Fixing extremely slow Git commands on Windows on a corporate network

tl;dr Set %HOME% on Windows to a non-networked directory

Git had terrible performance on my Windows laptop at work.

git branch could take 15 seconds to run, while git status could take 30 to 60 seconds.

I initially suspected the workplace virus scanner, but the actual cause was a network drive.

When reading .gitconfig, Git looks in %HOME% first1. If %HOME% isn’t defined, Git defines it internally as %HOMEDRIVE%%HOMEPATH%2.

On my machine, %HOME% was unset and %HOMEDRIVE% was mapped to a network drive.

Setting %HOME% to my local user directory fixed the problem immediately.