How to load default profile with Selenium when Chrome is already open?
The answer is you cannot open two session with 1 user-directory. Web-driver won't let you do this, It is like to rename a file in Windows when the file is open.
If you want to open chrome without user-dir, you can simply open with --incognito it will not store anything or use user-dir.
Otherwise you have to close the session with driver.quit() at the end of the test (teardown). So you can run the next test without problem.
Or you can use another user direcotry path, so the sessions will not interfers each other