This was a common problem with past versions of MAMP and it continues to happen for some users in version 4.x. Fortunately, the fix is easy. The problem is that when exiting MAMP the MySQL processes continue to run and are not stopped.
- Quit MAMP. You may have to force quit when this happens as it does not shut down correctly.
- To show any MySQL processes currently running, open Terminal and from the command prompt run:
- Next, kill the two MySQL processes by running the command below.
- To verify they no longer exist, we’ll grep for mysql again and you should not see any processes returned.
- Now launch MAMP again and MySQL Server start normally.
pgrep mysql | xargs kill -9