Cannot see Android 6 BLU R1 HD phone with USB connectito Windows 10 PC

I have had no luck connecting to new BLU R1 HD phone to my Windows 10 desktop via USB.

I have tried 2 different USB ports & 2 different cables (which worked for my old phone).

I have "data transfer" enabled on the phone using MTP.

Nothing shows up in File Explorer, but I do see a new unknown device appear in the Device Manager under "Other". Properties show no Driver installed, but Update Driver s/w appears to find drivers locally in C:\Windows\INF or by searching online, however these fail to install with the same error.

The drivers for this device are not installed. (Code 28)

A service installation section in this INF is invalid.

To find a driver for this device, click Update Driver.

Any help will be much appreciated!

Look in the notification area on the phone. You might see a notification that phone is in charge mode. Tap on that notification should reveal a number of options from which you can choose File Transfer. This should enable the drivers to be installed which should happen automatically and the ability to work with you phones data in File Explorer

File Transfer was already ON (sorry my post used the wrong phrase, I stated "data transfer" was on). But I just tried this again to make sure that use File Transfer is "checked".

So that does not solve my problem.

I think the issue is on the PC Windows 10 side... with the device drivers, but I don't know ... @$%!

HELP still needed with this issue.

Have a look here:
How to install MTK USB driver for BLU and other Android smartphones - BlogTechTips

Yeah, it is an issue that BLU needs to issue a driver for Windows 10, I see some others complaining about that as well. Sorry my suggestion failed.

SOLUTION found for me, at "answers.microsoft.com", much simpler than most stuff I already tried (that did not work):

"manually install the MTP USB Device driver see if that fixes the issue for you. Right click on your phone (should be in Portable Devices) in the Device manager, on the driver tab click "Update Driver..." On the "update Driver Software" window select "Browse my computer for driver software" on the next windows select "Let me pick from a list of device drivers on my computer" then in the list of compatible hardware devices, select "MTP USB Device" click next and your phone should be working again."

Additional advice from Ch863 on the answers.microsoft.com that I did not have to use:
"If you don't see MTP USB device in the list of compatible hardware, manually install the MTP USB device using the Add legacy hardware wizard. (Add legacy hardware -> Install the hardware that I manually select from the list (Advanced) -> in the list select "Portable Device" -> in the next list pick "MTP USB Device" then install it. Once it's installed redo the steps I gave you in the previous paragraph, the "MTP USB Device" should be showing now in the list of compatible hardware. "

Great, I had thought about suggesting a manual install of the Windows default drivers but that usually is not necessary. Must be something specific to how your device reports itself that causes the issue.

Glad you got it sorted.