windows won't install Arduino driver

Mega 2560
The bd works fine on my laptop printing via Repetier Host. It shows up as a USB-SERIAL CH340
On my desktop it used to work with ver 8. I upgraded to 12 and now Windows won't install the driver.
I tried rolling back to ver 9 - same
I tried installing ver 8 driver, no dice
I tried driver1_CH340 and driver2_CH340
driver1 didn't work at all and driver2 came back with an error after it at least tried.
Anyone got an answer??? Is it Arduino or Windows???

Have you tried the board with nothing connected to it and a simple blink sketch ?

Have you tried the loopback test pinned to the top of the forum ?

Almost sure there isn't a V8 IDE do you mean board manager ? or something else ?

ver 1.6.8
The bd works fine.
I compiled and loaded via my laptop, so it is something to do with windows 10 on the desktop.
Sure getting tired of this breaking all the time.
But I can't find this issue. Just thought someone else may have had the same issue with Arduino and found it.

AHH that makes more sense 1.6.8…

There have been a few issues with 3d printer firmware on megas maybe do a “search” of the forum otherwise

On your win 10 machine what type of USB ports are you using 2.0 or 3.0 as there are some issues with USB 3.0 (not all but enough) ?

Did you use the same cable that works on your other machine ?

Can you not see ANYTHING in device manager under com ports or other unidentified hardware etc. ?

Is IDE 1.6.8 the max version that repetier will work with ? as there are quite a few versions from there ?

The problem has nothing to do with the firmware. The printer works fine on my laptop. It is a driver issue with Windows and maybe specifically Windows 10 latest build 1607

RE USB3 ports - as misunderstood as they are - there are 2 - two - sets of contacts in a USB 3 connector. If you plug a USB 2 into a USB 3 socket, it will make contact with the USB 2 pins, which is a completely different circuit. My mega 2560 - and most all Arduino bds are USB 2. Therefore, they don't even touch the USB 3 pins, IF by some chance you found a USB 3 cable to use to connect it. So no problem can be attributed to a USB 3 connection unless the bd is capable of using USB 3.

Same cable used.

As I stated, the port in device manager showed up as a USB-SERIAL CH340 with a problem and Windows cannot find/install a driver. The Arduino driver doesn't install and the & drivers didn't work either.

I found the answer.... - it seems that the driver contained in the distribution and a few others posted are not working reliably with Windows 10 on some systems. My desktop stopped working but my laptop was OK.
I found a driver at the mfg site that worked first time.

Try it if you have this issue.

This may be something the Adruino folks want to address in their distribution.

RE your USB 3.0 assertions.

Whilst almost spot on you failed to take into account the chipset and or its implementation.
It is a KNOWN issue but beyond Arduinos control.

I also have USB 3.0 and pretty much all my cables are USB 2.0
If I plug a known working cable and board into a USB 3.0 port the board is not even recognised in any way shape or form. So I am sorry but problems CAN be attributed to USB 3.0 and should you need further proof then a good read of the forum will turn up more proof.

As for the CH340 driver issue. The CH340 is used on cheap Chinese knock offs and NOT by Arduino itself.
There is no reason for Arduino to implement a driver they do not use in the production of boards. and it is NOT included in the current (or past) distributions so I am not sure where you got your IDE ?

I never went down the CH340 route because you stated you had already done that. It appears you managed to get some drivers from an unknown source for your KNOCKOFF board. The link you finally gave is one of about three reputable sources.