A few versions ago Social Engine introduced a new method to help increase the speed of the programming.
Translation Performance is meant to Convert Language Pack CSV files to a PHP Array which in-turn would help increase the time taken to read the file that language was required but this has not always for many users.
Once a user has converted the language via the performance section of their Admin Panel their site seems to crash and become unresponsive unable to be access to anyone.
The only way to fix this problem is to follow this simple change in the database.
Go to database:
engine4_core_settings -> core.translate.adapter : and change “array” to “csv”
Click on Save
Now your site should be back to normal.