Hi, any one here had/has problem with usb COM port communication after latest Win10x64 update, on Anet A8? Printer now print only via SD card and connection from PC via USB doesn’t works. I tried uninstall and install Repetier-host back and still not working. I tried different USB port too with removed all other devices. Same result. When printer print from SD ok, is printer USB port on board ok too? How can I check if USB on board working?
Unfortunately there are a lot of potential causes for this. If the ANet A8 is using knockoff FDTI communcation chips, or if the communication chip’s driver isn’t “signed”. It’s possible during the update that it removed the unsigned driver, and Microsoft has made it even harder for people to run unsigned code or install unsigned drivers.
Type “device manager” in the windows start search, and open that up. Look for a com port that has a yellow error icon next to it. That will indicate a device which doesn’t have the driver installed.
Or use Linux. 
Hi, device manager is without errors. 3D printer is recongnized on COM4 as RAMPS but still invisible for ALL printing softwares :(. USB port on printer board is OK, tested with Octoprint with Raspberry.
Changed the baurd rate?
yes. this was my first step. Tried from 9600 up to end. Nothing new. Still same result.
SOLVED: RAMPS driver was set by W10 maybe to new version. I changed this driver from device manager to CH340 (from 2014) and … works now.
Yeah, another one chalked up to Microsoft sucks.