Why does Git switch my branches when I have modified files in the working folder?

Question

I have two branches. I changed some files while on one branch but did not add or commit them. The changes are in my working folder only. The changes are on tracked files but

Answer 1

You are probably referring to un-tracked files, not changed files. Un-tracked files where never added or committed to any branch, and they stick around when you switch branches.

If you change a tracked file, git won't let you switch branch until you do something with it (commit, discard the change, etc...).