External hard drive returns a “The semaphore timeout period has expired.” error
I haven’t used my pretty much full 2TB external hard drive in a few months and wanted to grab some movies off it. But when I plug it into my laptop it either won’t show up in my computer or it shows up in device manager and the eject tab shortcut on start menu but I can’t actually access it.
But suddenly last night it showed up on my computer but took ages to load into the hard drive. Then when I got in and tried to access any of the folders on it, it came up with “The semaphore timeout period has expired.”
What can I do to access the data on this drive?
52 Answers
Disconnect all USB devices. Reinstall all USB drivers. If you're on Windows 10 it will automatically do it for you if you restart your machine after uninstalling the drivers.
Seen elsewhere, a semaphore is a hold on the drive by some other process or application. Something is basically telling the computer that it's already using your HDD, or the specific portion of it which you're trying to access.
I got the semaphore error while copying files. leaving the error on screen, I ejected the drive via the system tray, unplugged and re-inserted the drive and clicked try again. File copying resumed after that. So basically by ejecting the drive, I forced whatever was holding that portion of my drive to let go of it.
I wish MS would make a real fix for this though. It is very annoying to constantly have to eject then reinsert the drive to resume copying large numbers of files. I even tried formatting and reinstalling USB drivers to fix the issue to no avail. Done an error check too on the drive and no problems there. Drive gives absolutely no other signs of failure, and the enclosure is brand new.
Edit: This seems to either be a problem with USB 3.0 connectivity because plugging a USB 2 Micro USB cable in instead (obviously slower) doesn't give the errors. Another possible culprit, if using a HDD caddy to house an old HDD, is that the HDD's circuitboard on the underside could be touching the casing of the caddy - causing short circuiting. The semaphore could be a result of that. I say this because I placed a plastic sheet in between mine and the error went away.
