This application has failed to start because libmcrypt.dll was not found...

I installed Apache without a hitch. Got the lovely “It works!” page, and then moved on to the PHP install. After trying the auto-install and binary packages, Apache simply would not start and would throw the following error in the Windows Application log:

Faulting application httpd.exe, version 2.2.14.0, faulting module php5ts.dll, version 5.2.11.11, fault address 0×000f330d.

I tried to Start > Run > “cmd” > “C:\php\php.exe -v” [enter] and kept getting DLL errors like “This application has failed to start because xyz.dll was not found. Re-installing the application may fix this problem.” I started tracking down the DLLs, but every one I fixed would expose another missing one.

Finally, I stumbled onto this PHP bug report where bwacker listed some of the same DLLs I was having trouble with. I commented out the lines referencing those DLLs in the php.ini file. The errors disappeared, and Apache started right up!

Here is bwacker’s list. Not all of the references were in my php.ini, but removing the ones that were there did the trick.

;extension=php_ifx.dll         needs ISQLT09A.DLL
;extension=php_iisfunc.dll    not in /extensions
;extension=php_mcrypt.dll    needs LIBMCRYPT.DLL
;extension=php_oci8.dll        needs OCI.DLL
;extension=php_oracle.dll    needs OCIW32.DLL
;extension=php_printer.dll    not in /extensions
;extension=php_sybase_ct.dll needs LIBCT.DLL and LIBCS.DLL

Obviously, if your application requires any of those DLLs, you will need to resolve the absences, but most of you will not need them.

but still got this message : Cannot load mcrypt extension. Please check your PHP configuration.

Hope this saves you some time!