The guest mode was actually one of the highlighted security feature of lollipop when it was initially announced. I have personally been waiting for something of this nature for quite some time. When infinix released their lollipop update, I was surprised that this feature was dropped.
[img]http://4.bp..com/-7LW4wnNoYMg/VniShyUCssI/AAAAAAAAK7c/zy3wkBv5zSI/s1600/wEHOqBmMH2IIwAAAABJRU5ErkJggg%253D%253D.jpg[/img]

With the guest mode, you can give your phone to anybody and be rest assured that your files and app data are completely safe and un accessible by just creating a separate account.

With the guest mode, you can give anyone access to your mobile phone while completely locking them out of your personal data. This means once you open a guest account, you will get a completely new interface with just installed apps and you can go ahead and login your Google accounts and also make use of any of the available apps without interfering with anything of your files or data.

In this tutorial I will show you how to manually add the guest mode to your lollipop device, most especially infinix and also how to enable it on all Android device.

Requirements:
Rooted Android device.
File manager (in this tutorial I will be using both es explorer and root explorer).

Tutorial 1 ~ With Root explorer:
=> Click on the "+" sign at the bottom of the screen and select root tab.
[img]http://3.bp..com/-Mo2eAsT0J5M/VniPvw3jh6I/AAAAAAAAK6s/8NDcwX72ucg/s320/lollipop%2Bguest%2Bmode%2Byomitech.jpg[/img]
=> Open the system folder.
=> Long press "build.prob", select open with.. And choose text editor.
=> Copy and paste the codes below in your build.prob just as shown in the screenshot below:
fw.max_users=3
fw.show_multiuserui=1
[img]http://1.bp..com/-1HAleitv-sE/VniPwWXToTI/AAAAAAAAK64/TIYHYyd1emY/s320/infinix%2Blollipop%2Bguest%2Bmode%2Byomitech.jpg[/img]
=> Save and reboot your device.
That's all!

Tutorial 2 ~ With Es Explorer:
=> First you have to enable root explorer by clicking on the menu option, scroll to the bottom and turn on root explorer.
http://4.bp..com/-MvTHWFjK9To/VniPx23BFWI/AAAAAAAAK7Q/-5vANRMqStQ/s320/yomitech.com%2Binfinix%2Bguest%2Bmode.jpg
*you will see a pop-up asking you to grant Es Explorer root access, just click on yes.
=> After that, click on the menu again and select device.
[img]http://1.bp..com/-tUhz9SQeHQ8/VniPvascP-I/AAAAAAAAK7U/w1Y5ob-MHfM/s320/infinix%2Bguest%2Bmode%2Byomitech.jpg[/img]
=> Open system folder.
=> Click on build.prob and open (preferably with Es editor).
=> Copy and paste the codes below in your build.prob.
fw.max_users=3
fw.show_multiuserui=1
[img]http://1.bp..com/-1HAleitv-sE/VniPwWXToTI/AAAAAAAAK64/TIYHYyd1emY/s320/infinix%2Blollipop%2Bguest%2Bmode%2Byomitech.jpg[/img]
Save and reboot your device.
You have just successfully added guest mode to your device. The next thing will be how to enable it.

How to Enable Guest Mode on All Lollipop Devices:
=> Swipe down the notification panel twice or swipe it once with two fingers.
=> Click on the user icon at the top right of the screen.
=> You should see 3 icons, just click on add guest.
=> Your phone will initialize for a couple of minutes and the guest mode will be enabled.

~To go back to your initial account, first go through step one and two then select your main account.

If you have any question, feel free to drop it in the comment box below.
http://www.yomitech.com/2015/12/how-to-manually-add-and-enable-guest.html

Great job...i've done dis long ago ....so i'll only tell u the dangers of doing it......if u do this , anytime u reboot your phone, your phone storage folder in your fone file manager will disappear and u can't watch videos or view pictures saved in ur phone storage except with third party apps like es file explorer....and to solve the problem u will have to remove guest mode and remount sdcard and storage, system etc via custom recouvery and reeboot to see ur phone storage folder......so for phones that didn't come with it leave it at that or go ahead if u know dat there's nothing that will make u reboot your fone