OK, Ive tried tried everything suggested here and everywhere else. I cannot get windows 10 to recognize the USB port with the CH340 clones. Reinstalled FTDI drivers and then tried to go back to the CH341SER drivers but I keep getting the "no 64 bit .INF found" error. Also tried several different cables. I know this has probably been asked 1000 times but I am losing hope. Thanks
I had no issue using the CH340SER.exe drivers on either of my Windows 10 x64 systems.
This is the official one : http://www.wch.cn/download/CH341SER_EXE.html
Which one did you use ?
Reinstalling FTDI is not needed. They are two drivers for two different usb products.
Try to install the CH341SER once more, and restart your computer.
It is possible that something is wrong in the settings of Windows 10 ow with the disk. Can you run a disk check ?
Koepel:
This is the official one : CH341SER.EXE - 南京沁恒微电子股份有限公司
Which one did you use ?Reinstalling FTDI is not needed. They are two drivers for two different usb products.
Try to install the CH341SER once more, and restart your computer.
It is possible that something is wrong in the settings of Windows 10 ow with the disk. Can you run a disk check ?
That's the one I used. Ive reinstalled and restarted several times. One thing I don't fully understand about the 340 driver is when I run the executable it says the drivers were previously installed even after I removed them and if I try to manually install the drivers through the device manager I get the driver not found error. I tried connecting to the nano on another computer with no luck. I think it is just faulty.
If you've only checked with one device, it could very well be a bad device, if it's not known working on other systems.
I'm pretty sure those el-cheapo clones that cost less than a cup of coffee aren't tested before the sellers throw them into bags without static protection, slap on an false customs declaration and drop them in the mail... That said, I have abused the hell out of CH340G's and have yet to break one.
DrAzzy:
If you've only checked with one device, it could very well be a bad device, if it's not known working on other systems.I'm pretty sure those el-cheapo clones that cost less than a cup of coffee aren't tested before the sellers throw them into bags without static protection, slap on an false customs declaration and drop them in the mail... That said, I have abused the hell out of CH340G's and have yet to break one.
I have a couple of "genuine" units coming in so I will try again with those. Putting this one on the back burner for now.
1khenegar:
OK, Ive tried tried everything suggested here and everywhere else. I cannot get windows 10 to recognize the USB port with the CH340 clones. Reinstalled FTDI drivers and then tried to go back to the CH341SER drivers but I keep getting the "no 64 bit .INF found" error. Also tried several different cables. I know this has probably been asked 1000 times but I am losing hope. Thanks
CH340 | arduined.eu I had luck with this site but I had problems uploading my real Arduinos after I got that program in but I fixed it by just uploading the Arduino program again. Hope this is a help.
Koepel:
This is the official one : CH341SER.EXE - 南京沁恒微电子股份有限公司
McAfee warns that the site is a risk and if you ignore it and download McAfee warns the exe has trojan.
Asterion:
McAfee warns that the site is a risk and if you ignore it and download McAfee warns the exe has trojan.
Odd as many of use use that site.
Its the "goto" one for the drivers and none of the extensive security here has ever even hinted at it or the drivers being of any sort of risk.
There again I don't use Norton or Mcafee bloatware and haven't for a number of years as I spent too much time fixing customers slow computers after those were installed.
Couple of remarks:
CH341SER.EXE - 南京沁恒微电子股份有限公司 is the site of the actual manufacturer. So if you don't trust them, don't use the CH340
1khenegar:
and then tried to go back to the CH341SER drivers
There is no such thing as going back to them. A driver is installed or it's not. Being linked to a device is another story. And the FTDI drivers have nothing to do with the CH340. If you have a CH340 you should not try to point to the FTDI drivers or vice versa but Windows should tell you that.
1khenegar:
One thing I don't fully understand about the 340 driver is when I run the executable it says the drivers were previously installed even after I removed them
How did you do that? Just removing the device doesn't delete the driver. It just un-links them Sometimes Windows gives you the extra option to do so but if it thinks it's still in use it doesn't.
But if you have the CH340 driver installed, then plug in the CH340 and Windows will just link the driver for you. No need to dig through .inf files. But the fact you "installed" FTDI drivers for it I start to think it's NOT a CH340 but just a Chinese/counterfeit FTDI which will install with the latest FTDI drivers but just will not work. Google "FTDI gate".
Just adding my 4 penny worth -
My Uno(cheap ver) works with win 7 and not win 10 I've done all the things suggested and sitll no luck.
Things I've tried are getting the download from wcn.com and using CH340 driver.
My ports are USB 3.0, as suggested I tried lowering the receive and transmit buffer in < device manager> <USB serial CH340 (COM3) properties>
is it worth getting a USB 2.0 buffer?
Changing the buffers for the USB port will hardly ever work. (return them to the original values)
However inserting a half decent self powered USB 2.0 hub has been seen to fix a majority of USB 3.0 port issues.
Also it is always best under win 10 to install drivers with "driver enforcement" turned off and with FULL Administrative privileges. That should not normally be needed but has in the past fixed drivers issues.
Success! My Uno now works on my win 10 pc.
The solution was as suggested by ( ballscrewbob - thank you) disable driver signature enforcement.
This was done according to "How to geek". - Enable test signing mode. - Windows power shell (Admin) and to testsigning off when through.
CH341 driver then works
Sweet..I love a quick fix (but proper one) 
Thank you
RichardMorgan:
Success! My Uno now works on my win 10 pc.The solution was as suggested by ( ballscrewbob - thank you) disable driver signature enforcement.
This was done according to "How to geek". - Enable test signing mode. - Windows power shell (Admin) and to testsigning off when through.
CH341 driver then works
How did you do this? I really couldn't do anything. 
There are multiple ways to turn off "driver enforcement" from single instance to multiple instance to always.
Just google "turn off driver enforcement (your OS HERE)"
The CH340/341 drivers are HERE
Hello,
Now I am back to use arduino clone with ch340 driver. I instaled ch340 driver x64, but not working.
Can someone please write step by step instruction to help me?
I am using windows 10 and arduino 1.8.5.
Thank you !
Did nothing else in this post help ?
Everything is in this thread for CH340 and win 10.
I googled "turn off driver enforcement" and did all steps. After that I re-instaled ch340 driver fallowing your link.
But nothing. 