Normally for an Android based phone, you can mount it as a drive by trying steps or similar: Settings -> Wireless&Wifi -> USB Tools -> Connect USB mass storage and then plugging your Samsung Galaxy device into the PC. But what's wrong out there with Samsung Galaxy S3 or Note 2?
The fact is – it seems Samsung has disabled the option for some reasons (probably because of security concerns). The device now uses MTP (Media Sharing Protocol) and PTP, which aren't very useful for everyone. For example, for Samsung Galaxy S III, instead of USB mass storage, it only features MTP, which is not as easy to use and fast, so many prefer UMS instead.
Then how to enable UMS mode for Samsung Galaxy S2, S3, Note 2 or whatsoever...?
Steps to Enable USB Mass Storage mode
First of all: you'll need to root your Samsung Android. Here is a step by step Android Rooting guide which you can follow for the Samsung Galaxy S2/S3 or Note 2.
For Samsung Galaxy S3
- Download the apk file here.
- Copy the apk to your device and disconnect it from your computer.
- Then install the app on your device and follow the instructions given by the app.
- Once the app is installed, you can open it and select the option you prefer for file transfer, which is very easy.
For Samsung Galaxy Note 2
- Download SGS3 Easy UMS here.
- Then you will have to launch the app, grant it root access when you're asked for it, and choose the way you want to mount your device on the PC.
- It's very easy and you will only have to tap one button to switch from one mode to another.
Kind note: before starting the procedure, make sure you've backed up the data on your Samsung Galaxy, just in case. If you do encounter data loss during or after the procedure, check here (photos & videos) or here (text messages) for recovery solutions. Android backup options can be seen in this article.
Good luck!