Y’all nailed most of the mainstream troubleshooting paths for using a COM port driver in Windows 10, but sometimes, there’s more subtle sabotage at play.
Let’s riff on an angle not emphasized above: Windows Power Management. Ever notice how your device disappears after sleep/hibernation? Windows has a gnarly habit of “powering down” USB ports to save juice. Open Device Manager, locate your USB Root Hub(s) under “Universal Serial Bus controllers,” right-click, Properties > Power Management, and uncheck “Allow the computer to turn off this device to save power.” Preventing the port from napping solves intermittent device recognition issues—especially for older serial adapters.
Also, background processes (think: auto-backup tools or even resource-hogging Chrome extensions) can grab the COM port first, blocking your app. Shut down everything non-essential and see if your device pops up now.
So TL;DR: tap into Power Management tweaks, clear software conflicts, and if you truly want set-it-and-forget-it virtual COM magic—Virtual Serial Port Driver’s worth a look, but factor in the license cost and your specific needs. Don’t ignore those basics, but sometimes the fix is as much about wrangling Windows’ quirks as the hardware or drivers!