I had the same problem and wrote this post with the answer:
The fix is to remove/disable /System/Library/LoginPlugins/FSDisconnect.loginPlugin
The following steps should sort you out:
- Click on the spotlight icon (magnifying glass) in the upper right of your screen
- Type in ‘terminal’
- Click the ‘Terminal’ icon (black with white border) under applications
Type in the following command (and hit enter):
sudo mv /System/Library/LoginPlugins/FSDisconnect.loginPlugin /System/
It will prompt you for your user password. Type it and hit enter again
- Reboot
This just moves the plugin to /System so you can restore it again if needed by replacing step #4 with sudo mv /System/FSDisconnect.loginPlugin /System/Library/LoginPlugins/.