Why does the script hang on session_start?

Question

PHP

Transferred an online store to OpenCart from hosting to a local Openserver. On hosting and on test local pages with session_start, this problem does not arise. And the store page is just waiting for a response until max_execution_time expires, no other errors occur. Insert session_start(); die; to the top of index.php gives a similar result. I'm a newbie in development, I can't figure out where to dig.
PHP version - 5.6-x64, opencart - 2.0.1.0

Answer 1

I'll duplicate from the comments in response:
It looks nothing unusual, but it "freezes", even if you make index.php with session_start on any other host? If it "hangs" while something else "works" (the request has left and has not yet been processed) - then this is a classic error in accessing the sessions file - transfer the sessions to memcache / redis, especially since you already have them connected.