Fix the Device Which Does Not Exist Was Specified Error

When Windows displays “A Device Which Does Not Exist Was Specified,” it is usually returning System Error 55, also known as ERROR_DEV_NOT_EXIST. This commonly occurs when File Explorer or an application tries to open a mapped network drive, USB device or other storage location that Windows can no longer find.

The message does not always indicate failed hardware. An old network mapping, disconnected VPN, changed USB drive letter or outdated application shortcut can produce the same error. Identifying the trigger before changing settings prevents unnecessary data loss and makes the repair much faster.

Symptom	Likely cause	First action
A mapped drive such as Z:\ will not open	Stale or disconnected network mapping	Check the drive under This PC
The error appears after reconnecting a USB device	The device received a different drive letter	Review Disk Management
A shared folder fails after a VPN or internet outage	Network or saved credentials are unavailable	Reconnect the VPN and test the share
An application cannot find a previous folder	The program still points to an old drive path	Check the shortcut and program settings

Confirm the exact failure

Start by noting what you clicked when the message appeared. If opening Z:\ causes the error, the problem is probably a mapped drive. If starting a particular program causes it, check that program’s saved file locations. Opening a local folder on C:\ can help confirm that Windows itself is still functioning normally.

Think about recent hardware, network or software changes. Australian offices in Sydney, Melbourne and Brisbane commonly map Z:\ or S:\ to a NAS or file server, so moving offices, replacing a router or renaming a server can leave a valid-looking drive entry pointing to equipment that no longer exists. Local support staff may hear a user describe this as the shared drive having “dropped off”, but the underlying issue remains a broken reference.

Clear stale drive mappings

Open File Explorer, select This PC and right-click the affected network drive. Choose Disconnect to remove the stale mapping; this does not delete the files stored on the remote server. If the option is unavailable, open Command Prompt and run net use to list connections. Remove the relevant mapping with net use Z: /delete /y, substituting the correct drive letter.

Reconnect the drive through Map network drive and enter the current network path, such as \\server-name\shared-folder. Select Reconnect at sign-in if the mapping is needed for work every day. If the server has moved to a new address, update the path before recreating the mapping rather than repeatedly reconnecting the old one.

Check USB and hardware changes

For a USB drive, reconnect it directly to the computer and try another port. External drives can lose their assigned letter after a restart, firmware change or disconnection. Open Disk Management and look under Disk Drives. If the device appears but has no letter, assign it a letter and then update any shortcuts or software that used the previous one.

If Windows does not list the device, test the cable, enclosure and another USB port. Do not initialise, format or repeatedly accept a formatting prompt if the drive contains important files; these actions can make recovery harder. Hardware failure is less common than a stale mapping, but a drive that no longer appears in Disk Management needs a data-recovery assessment rather than further Windows configuration.

Restore network access and authentication

Network shares require three things: a working connection, an accessible server and valid credentials. Check the internet connection, open the router administration page and confirm that other network devices are online. NBN is widespread in Australian cities, but regional and remote properties may rely on fixed wireless or satellite service. A brief outage around Perth, Alice Springs or an isolated property can therefore leave a mapped drive inaccessible even when the PC and server are undamaged.

Open the share through its UNC path before trying the mapped letter. If it requests a password, remove an outdated entry from Windows Credential Manager and reconnect with current details. Also reconnect any required VPN. Office relocations in Melbourne and Sydney often produce this fault when a file server gets a new hostname or IP address, while hybrid staff may encounter it after switching between VPN profiles.

Repair programs that remember old paths

Check the shortcut’s Properties and confirm that its Target and Start in fields still point to an existing location. Applications such as desktop accounting packages, customer-management software and older document systems may also store a path such as D:\Clients internally. Australian businesses using programs such as MYOB Desktop alongside local document folders can be particularly affected when Windows or a server upgrade changes that arrangement.

Update saved folders within the application first. If no setting is available, reinstalling the program may reset its configuration, but back up bookmarks, templates and client files beforehand. Avoid editing the registry simply to create a missing drive letter: that can hide the original problem and cause the application to overwrite data in an unintended location.

Run targeted Windows repairs

After removing old mappings and correcting saved paths, restart Windows and install any pending updates. If the error continues across several applications, open Terminal or Command Prompt as administrator and run DISM.exe /Online /Cleanup-Image /RestoreHealth, followed by sfc /scannow. DISM needs an internet connection, and the system file check can take some time. These commands repair corrupted Windows components but will not restore a disconnected server or failed USB device.

For broader network faults, running netsh winsock reset and netsh int ip reset can rebuild the Windows network stack. Restart afterwards, as internet connections and VPN software may need to be reconfigured. If the problem affects only one Windows account, create a temporary local account and test the same drive there. A working account points toward a damaged user profile, while identical failures in both accounts suggest a device, server or network issue.

Test the fix and prevent recurrence

Return to the original action that produced the error and confirm that the drive, folder or application opens correctly. Restart once more to ensure the mapping survives a normal sign-in. Repeat the test under the account used for daily work, especially if the original failure occurred only after logging into Windows.

For business systems, record the drive letter and UNC path in the organisation’s support notes. Mapped drives should point to stable server names rather than temporary IP addresses, and scheduled backups should use a verified path. Maintaining a separate backup of Australian client, financial and tax records protects against the larger risk if a NAS, drive or account becomes unavailable.

If the error survives these checks, Movian Security can trace the drive reference, inspect Windows services and storage settings, remove conflicting software and recover important data where needed. This is particularly useful for small businesses that depend on a local PC repair shop or managed IT provider rather than a manufacturer’s support centre, and it avoids treating a recoverable mapping problem as a complete computer replacement.