I just purchased an Infinix Hot 4 and a Nexus phone after running few updates on it, i noticed my Computer doesn't detect my phone when it's connected via USB.
I realized that this was a common issue with new Android devices.
This mostly happens after a recent update and is caused by bad Android USB drivers loading in place of good ones, So the computer fails to recognize the device.
There are two ways to fix this issue.
FIX 1: ENABLE USB DEBUGGING (ADB)Android debug bridge also know as USB debugging allows the user to gain direct access to the main file system of the Android device from any PC. When USB debugging disabled, users will only be able to interact with their device media storage, such as the SD Memory card.
Click Here To Learn How To Enable USB Debugging.After enabling USB Debugging try reconnecting to your Computer.
If FIX 1 doesn't work, try FIX 2 below
FIX 2: Remove Bad ADB Drivers Or Reinstall MTPIf your Android device is not recognized due to bad ADB drivers or missing MTP driver this should fix it.
Installing MTP USB Device driverPress
Windows Key + X on your system and select
Device Manager from the menu.

Look for
Android device, right click it and choose
Update Driver Software.

Select browse my computer for driver software.

Next! click Let me pick from a list of device drivers on my computer.

Select
MTP USB Device and click Next.
Reconnect your Android device after the driver has been installed.
Your Android device should now be recognized.
You can also try uninstalling the previous Android ADB driver located there

plug in your Android device into your Computer via USB. The correct ADB drivers should load. You can verify by going to Device Manager in Windows. Right click and select Uninstall.

Make sure you tick the box for Remove Driver.

Download and install a fresh
Universal ADB Driver here.
And Install.
If the entire method does not work for you, try thisOpen your device manager look for the name of your device which has
ADBIf you don’t see anything with “ADB” in the name, you may have to look elsewhere. I found the Nexus 6P under “Portable Devices,”
Click on the
Update Driver Software
Click
Browse my Computer for driver software
After that select
Let me pick from a list of device drivers on my computer
Now you will see a long lists of software select
Android device or
Android Phone
On the next screen select
MTP USB Device then click
Next.

Your device driver will then install, and your Android device will be recognized as a multimedia device and can be discovered in the File Manager.
Tell us which method worked for you in the reply section