I have an E-tel(curiosity i110) mobile device running on android 4.42. I tried to install Apps using APK files to my SD card but i couldn't. My problem is that I cannot move Apps which already installed to SD-card. When I check app manger, I seems move to SD card button is fade out. My question is, why my android OS blocked this feature? What can i do? How to select default APK installer as SD card without rooting?
In your case, if move to SD card option is fade out, then you can't move apps to SD card. The apps installed by user could be moved to SD-card to save internal storage.
There are some system apps which could not be moved to SD-card because OS doesn't allows that.
This may be also app specific, as whatsapp or any game, because block to move their data. Some apps you can move or some you can't.
If it is not possible without rooting, you can go to root your phone and install Link2SD , by which you can create a partition on your SD card and install apps on that.