If you just updated to Mac OS X Yosemite and MAMP stopped working for you, this tutorial will provide a very simple fix.
The problem is that after starting MAMP, the Apache Server won't start.
Open up Finder in your Mac, then:
- Go (top menu)
- Go to Folder...
Type in /Applications/MAMP/Library/bin then click Go
Rename the envvars file to _envvars
Go back to your MAMP control panel and click the Start Servers button.
Voila - It's Fixed
Now you can use MAMP as usual. Enjoy!