You connect a new hard drive, but it never appears where you expect to save your files. The next step depends on whether the computer detects the hardware or the disk needs setup. Start with the connection, then use the Windows or Mac checks below to find the right fix. Only initialize or format a drive after confirming it is empty or its files are backed up.
Start with the connection
Disconnect your external drive, then reconnect it directly to another USB port on the computer, bypassing your hub or dock. Try another compatible connection cable, and connect the drive’s required external power supply.
Shut down the computer, then switch off the externally powered drive. Restart the drive, then restart the computer.
On Windows, open Disk Management from the right-click menu on Start, then select Action > Rescan Disks. Always shut down the computer before changing an internal drive’s cable.
Find out whether Windows detects the disk
An empty disk without a usable volume still needs setup before it can store your files. Open Disk Management from the right-click menu on Start. Locate the intended disk before changing anything.
Check its status. Offline means the disk needs to be brought online. A genuinely empty disk marked Not Initialized needs initialization, while empty Unallocated space needs a new volume.
Stop before initializing or formatting a drive that contains files you need, even if it reports Not Initialized or RAW. If the disk is absent after a rescan, skip the setup steps and continue to the device-driver and internal-connection checks below.
Restore an offline disk or missing drive letter
For a disk marked Offline, select Online from its disk entry’s right-click menu in Disk Management. For an existing data volume without a drive letter, open Change Drive Letter and Paths from the volume’s right-click menu. Work only on your intended data volume, never a protected EFI or Recovery partition.
Select Add for a missing letter, or Change for a conflicting letter. Next, select Assign the following drive letter. Choose an unused letter, then select OK.
Select Yes when prompted. If access is still missing, follow the disk’s status: initialize a genuinely empty, uninitialized disk or create a volume in empty unallocated space. For an existing formatted volume that remains unusable, continue with the driver checks without erasing it.
Initialize a genuinely empty drive
For a new disk with no needed files, use Disk Management with administrator permissions.
- 1.Confirm the identity of the disk you want to set up.
- 2.Right-click that disk and select Initialize Disk. Some USB devices support formatting and drive-letter assignment without initialization; for those devices, continue to volume setup below.
- 3.Confirm that the correct disk is selected in the dialog.
- 4.Select GPT for a modern computer.
- 5.Select OK. Once the empty disk shows Unallocated space, create its volume using the next section.
Turn unallocated space into usable storage
Creating and formatting a volume makes empty, unallocated space usable for files. Open New Simple Volume from the right-click menu on the intended disk’s Unallocated space in Disk Management. Select Next.
Choose the volume size, then select Next. Choose a drive letter, then select Next.
Configure the file system and formatting options on Format Partition, then select Next. Select Finish.
For an existing empty volume that needs formatting instead, open Format from that volume’s right-click menu. Formatting erases existing data. Select the required file system and formatting options.
Select OK. Select OK again to confirm.
Check for a disabled device or driver problem
After connection checks, use the option below that matches the affected device’s error or driver history.
- 1.Right-click Start and open Device Manager.
- 2.For an affected disk or controller disabled with Code 22, select the device, then Action > Enable Device.
- 3.For a malfunctioning disk or USB device with a detection error, right-click that device and select Uninstall device > Uninstall. Select Action > Scan for hardware changes to redetect it.
- 4.To reinstall the affected driver by restarting instead, right-click the device and select Uninstall device > Uninstall. Then use the right-click Start menu and select Shut down or sign out > Restart; Windows attempts to reinstall the driver after the restart.
- 5.For available hardware-driver updates, open Start > Settings > Windows Update > Advanced options > Optional updates. Select the applicable driver updates, choose Download and install, then restart.
- 6.If a driver update introduced the problem, open the affected device’s Properties > Driver > Roll Back Driver. Choose a reason and select Yes; restart if requested. Rollback requires administrator permissions and an available previous driver.
If an internal drive is still missing
Internal drives need a secure connection and a compatible motherboard port. The SATA and M.2 checks here apply to ASUS motherboards.
Power off the computer before working on its internal connections. Then reseat the SATA drive’s data cable and its power cable. Try another SATA data cable.
Move the data connection to another compatible motherboard SATA port, then try another power connector for the drive. For an M.2 SSD, reinstall the drive fully in its compatible slot while the computer is powered off. Secure the SSD’s mounting screw.
Check your exact motherboard model’s manual for SATA or PCIe M.2 compatibility and shared-port restrictions. Move the drive to a compatible, unshared port if its current connection conflicts with those restrictions. For a computer with firmware controls for individual drives or storage ports, enter BIOS/UEFI using the model’s documented startup key. Enable the relevant drive or port using that model’s controls.
Save the firmware settings and restart. A blank data drive does not need to appear as a bootable device.
If the internal drive remains missing, continue with the manufacturer’s model-specific hardware troubleshooting. For an external drive, test it on another computer. Persistent failure across known-good connections and computers calls for service or replacement.
When a new drive is missing on a Mac
Disabled disk-visibility settings hide mounted drives from Finder. Open Finder > Settings > Sidebar. Enable External disks for external storage. Enable Hard disks for internal disks.
Look under Locations in Finder. To show drives on the desktop, open Finder > Settings > General. Enable External disks or Hard disks for the drive you want to display.
On a Mac laptop with Apple silicon, unlock the Mac. Reconnect the drive. Select Allow in the accessory alert.
For a drive still missing from Finder, open Applications > Utilities > Disk Utility. Select View > Show All Devices to display physical devices and their volumes. Select the detected, unmounted volume. Click Mount.
For a detected formatted disk that needs repair, select its lowest volume. Choose First Aid > Run. Repeat the repair upward through its volumes, volume groups, containers, and finally the physical device. Supply an administrator password when requested.
For a genuinely empty drive that needs setup, select the physical device. Click Erase. This deletes existing data. Set Scheme to GUID Partition Map.
Choose the Format and enter a name for the drive. Select Erase, then select Done.
If the device is absent from Disk Utility, hold Option and choose Apple menu > System Information. Inspect the appropriate entry under Hardware to check detection independently of Finder.
Locked drives and the point to stop troubleshooting
Unlock supported secure Seagate or LaCie drives through Toolkit > Seagate Secure > Unlock: enter the drive password and select Unlock. For compatible Sandisk drives with an onboard unlocker, open SANDISK Unlocker > SANDISK Drive Unlock, approve the prompt, enter the password, and select Unlock Drive > Close.
For a supported drive detected by SeaTools 5 on Windows or Linux, select the drive and open Health > Quick Tests > Short Self Test or Short Generic Test, then inspect Results. SeaTools cannot diagnose hardware that cannot communicate with the controller.
Persistent failure across known-good connections and computers calls for vendor service or return and replacement. If the drive contains needed files, pursue data recovery instead of repeating initialization, formatting, or factory resets.
Frequently Asked Questions
Why is my new drive missing during Windows installation on a Dell PC?
On affected Dell systems using Intel VMD, load the matching Intel Rapid Storage Technology driver during installation. Download the driver for your exact Dell model. Select Extract. Copy the extracted files to USB. In Windows Setup, select Load driver. Select Browse. Choose the extracted VMD driver folder. Select OK. Select Intel RST VMD Controller. Select Next.
Does ordinary file storage require the manufacturer’s app?
No. Drive makers such as Sandisk state that their software is not required to store data on their drives; companion apps add optional features such as backup and password protection. A drive that has been password-locked must still be unlocked before use. Installing security software also does not add hardware-encryption features to an unsupported drive.
Can CHKDSK fix a hard drive that Windows cannot detect?
No. CHKDSK repairs a recognized formatted Windows volume. It does not initialize a blank drive or detect missing hardware.
Does the absence of a Windows disk-health warning mean my drive is healthy?
No. Windows disk-health warnings in Settings > System > Storage > Advanced storage settings > Disks & volumes cover NVMe SSDs, not HDDs or SATA SSDs. The absence of a warning does not establish those drives’ health.