This morning, after resuming my notebook (powered by Windows 8) from hibernation I noticed that some drives are missing from Windows Explorer. Two of my five drives were not seen in Windows Explorer but were visible in Disk Management. Computer users who have been using or used Windows XP, Vista, or Windows 7 operating system must be knowing that the issue isn’t specific to Windows 8 and present in previous Windows versions as well. The issue generally occurs when you resume your PC from hibernation or sleep. A drive may disappear from the Explorer if it doesn’t have a drive letter assigned. Besides, if the drive is disabled or offline, it may not appear in the Explorer. Users who are experiencing this issue can follow the given below methods to resolve the issue. Method 1: Step 1: Open Run dialog box, type diskmgmt.msc, and press enter key to launch Disk Management. Step 2: In the Disk Management, verify that the drive has a valid drive letter assigned. You should see a drive letter right next to the drive name. If it doesn’t have a drive letter, right-click on the unlabeled drive, click Change drive letter and paths. And if the missing drive has a valid drive letter and still not appearing in the Explorer, you need to check out for other possible fixes. Step 3: You should now see a small dialog named change Drive Letter and Paths. Click Add button, select a drive letter for your drive from the drop down menu, and then click Ok button. You should now see the drive in Windows Explorer. NOTE: If the Change drive letter and paths option isn’t available in the context menu, make sure that the drive is Online. If the drive is Offline, right-click on the disk number and click Online. Method 2: If the drive is not appearing even after assigning the drive letter, you may need to run the official Hardware and devices troubleshooter present in Windows 7 and Windows 8. Step 1: Type troubleshooting in Windows 7 Start menu search box and press enter key. And if you are on Windows 8, press Windows + W hotkey to open settings search, type troubleshooting in the search box and press enter. Step 2: In the left pane of Troubleshooting window, click View all to see all available troubleshooters in Windows. Step 3: Click Hardware and Devices troubleshooter to launch it, click Next to start scanning your PC for related issues. If issues are found, the troubleshooter will try to fix them automatically. And if the troubleshooter to fails to detect to the problem, close the troubleshooter and try out other possible fixes available on the web.