Git - git config - error: could not lock config file - Permission denied

Problem:

I am on Windows 10 and got this error:

$ git config --system --unset credential.helper
error: could not lock config file 
C:/Program Files/Git/mingw64/etc/gitconfig: Permission denied

How to solve it?
 

Solution:

Quick fix:
Under Windows open Git Bash as Administrator

Step by step:
1. Open Windows search
2. Type: Git Bash
3. Click second mouse button and select: Run as administrator
4. Go to your project directory:

cd "C:\path\to\our\project\name"

5. Execute command:

git config --system --unset credential.helper

On linux run this command with sudo command:

sudo git config --system --unset credential.helper