Apache child process exited with status 255

After lot of searching, trying, fixing, waiting and crying and before I give up, I want to take the last chance here for this bug... We're running on Microsoft Windows Server 2012, Apache/2.4.6 (Win64) OpenSSL/1.0.1e PHP/5.5.1. Periodically, at least 5-10 times within 24 hours, Apache crashing and restarting. Mostly twice. Because PHP crashed. The whole application is PHP, so configuring php as FastCGI won't solve the problem: Apache will not crash but PHP will. here some more info: Windows Event Log: Faulting application name: httpd.exe, version: 2.4.6.0, time stamp: 0x51e441d6 Faulting module name: php5ts.dll, version: 5.5.1.0, time stamp: 0x51e849b0 Exception code: 0xc0000005 Fault offset: 0x00000000000572d8 Faulting process id: 0xac0 Faulting application start time: 0x01d0a96634f3d129 Faulting application path: C:Apache24binhttpd.exe Faulting module path: C:PHPphp5ts.dll Report Id: 06409cc4-1568-11e5-93ff-d43d7edb03a9 Faulting package full name: Faulting package-relative application ID: Apache Log: [Thu Jun 18 06:13:44.284810 2015] [mpm_winnt:notice] [pid 2736:tid 392] AH00428: Parent: child process 2752 exited with status 255 -- Restarting. [Thu Jun 18 06:13:44.487977 2015] [mpm_winnt:notice] [pid 2736:tid 392] AH00455: Apache/2.4.6 (Win64) OpenSSL/1.0.1e PHP/5.5.1 configured -- resuming normal operations [Thu Jun 18 06:13:44.487977 2015] [mpm_winnt:notice] [pid 2736:tid 392] AH00456: Apache Lounge VC11 Server built: Jul 15 2013 20:45:22 [Thu Jun 18 06:13:44.487977 2015] [core:notice] [pid 2736:tid 392] AH00094: Command line: 'c:\Apache24\bin\httpd.exe -d C:/Apache24' [Thu Jun 18 06:13:44.487977 2015] [mpm_winnt:notice] [pid 2736:tid 392] AH00418: Parent: Created child process 4408 In PHP log nothing special and no pattern before crash. Also concurrent connections not affecting the problem - it's happens even when we have very few users. MySQL? But no errors pointing to this or I looking in wrong place? Windows? How to figure out? PHP/Apache configuration? Well, what else.. and why? Aliens... The main question is why PHP is crashing?.. Thanks in advance!