helm-locate defaults to case insensitive search for unix/linux platforms. But for windows the searches are done in case sensitive. The cause of the problem is that when given "-i" parameter the "es" command does case sensitive search. To be in line with other platforms this "-i" parameter must be omitted.
And the documentation of helm-locate also should be corrected which falsely claims that the "es" parameters are the same as "locate". "-i" parameter does opposite things for "locate" and "es"
* helm-locate.el (helm-locate-case-fold-search): Issue #115 New user …
(helm-c-locate-init): Use it.
You can use now helm-locate-case-fold-search which default to helm-case-fold-search which is himself 'smart by default.
A value of nil means: use -i on "locate" and don't use it on "es".
A value of t means: use -i on "es" and don't use it on "locate".
A smart value means use -i depending on value of pattern (See docstring)
BTW I didn't find where documentation claim locate takes same args as es.
for the documentation:
On Windows you should use Everything program that mimic locate, is very fast and dont need to update database manually. To use with helm-locate, you will need his command line namedes. Be sure to modify the PATH environment variable, to include path to the directory that containes. The arguments are the same than the ones inlocate`.