Here’s an interesting one. I couldn’t back up my Surface Pro 3 lately, because Macrium Reflect keeps failing right as the backup completes. In fact, the external USB drive I plug into the Surface Pro dock disappears from Explorer at the same time. Bizarre! That’s what had me figuring what’s involved in fixing Surface Pro USB drive drop this morning. An anomalous default registry setting on the Surface Pro 3 knocked out a whole raft of Power Options settings. This included the USB selective suspend setting, which I immediately suspected might be causing my problems. Poking around online I used “unable to unlock power options Surface Pro” to find what turned out to be a working solution.
When I first dropped into Power Options, USB settings — and a bunch of other stuff — was MIA. WTF?
Registry Edit Key to Fixing Surface Pro 3 USB Drive Drop
In researching the missing Power Options settings, I found a post from a NIC maker (ekahau) that mentioned a weird default in the Surface Pro registry setup. It turns out that
HKLM\System\CurrentControlSet\Control\Power\CsEnabled is set to “Enabled” (value: 1) on Surface Pro PCs (HKLM is an abbreviation for HKEY_LOCAL_MACHINE). This not only drops a bunch of settings from the Power Options control panel widget, it also sets the USB selective suspend to the “on” state in an unchangeable way. By modifying the value for that entry from 1 (one) to 0 (zero), I got the missing setting back in Power Options. Immediately after this change, Macrium Reflect backup completed successfully. To be on the safe side, I disabled it anyway when the unit is docked (or running off A/C power).
I’m incredibly glad I found the right search string for this still-mysterious Power Options setting. I’m not sure what changed recently on my Surface Pro 3, either through Windows Updates or firmware upgrades, to break what had been working since time immemorial. I am, however, relieved to find backup working properly again, and my external USB devices remaining attached and visible in Windows 10. FWIW, it’s running Build 18362.10022, which I believe is the latest Slow Ring Insider Preview release. There may have been something in this code base that mucked around with the power options and related USB settings. Who knows?