When your Android phone can not successfully connect to your computer, you should first make sure that the USB debugging in your cellphone is enabled. Moreover, the steps to enable USB debugging on Android phone vary from version to version, which is further illustrated below.
Tip: The Android version in mobile phones can be checked in Settings/About phone.
Step 1: Open Settings.
Step 2: Access Applications.
Step 3: Enter Development.
Step 4: Choose USB debugging and tap OK.
Example: Steps to enable USB debugging on Samsung Note 2 are as follows.
Step 1: Enter Settings in the Apps.
Step 2: Select Developer options in the Settings interface.
Step 3: Choose USB debugging by checking the box behind it, as shown in the following photo.
Step 1: Access Settings.
Step 2: Click About phone.
Step 3: Continuously tap Build number for many times until the system informs you that you've entered the developer mode, or tells you that you are now a developer.
Step 4: Return to Settings.
Step 5: Open Developer options.
Step 6: Select USB debugging.
Step 7: Tap OK or Yes to allow USB debugging.
Tip: For Android versions higher than Android 4.2.x, at the last step, the following dialog box will pop up. In this case, choose Always allow from this computer and click OK.
With the help of the above guidance, have you successfully enabled the USB debugging on your Android phone?