Is it a Virus?
✔ NO - Safe
Located in C:\\Windows\\System32\\drivers\\mountmgr.sys and digitally signed by Microsoft.
Warning
Kernel driver, expect normal low-level activity
Damage or tampering can impact all mounted volumes
Can I Disable?
✖ NO (Not Recommended)
Disabling mount manager can render disks unmountable and Windows unstable. Use with caution.
What is mountmgr.sys?
mountmgr.sys is Windows' Mount Manager driver, a privileged kernel component responsible for coordinating the mounting and dismounting of file systems and volumes. It manages when disks are prepared, assigns drive letters, and ensures newly connected storage becomes accessible in a controlled manner.
Mount Manager operates at the kernel level to coordinate volume mounting events, track device arrival, and coordinate with file system drivers. It ensures volumes are mounted in a stable sequence and manages cleanup during dismounts to prevent data loss.
Quick Fact: Windows Mount Manager orchestrates volume mounting during boot and device connect events to keep storage available reliably.
Types of Mount Manager Roles
- System Driver: Core kernel component that handles storage volumes and mounting requests
- Volume Letter Allocation: Manages drive letter assignments for newly connected disks
- Device Arrival Handler: Responds to plug-in events and initializes disks
- Unmount Coordination: Coordinates safe dismounts and cleanup when volumes detach
- Error Recovery: Works with the OS to recover from mount failures
- Registry/Config Interface: Interacts with system configuration to persist mounting behavior
Is mountmgr.sys Safe?
Yes, mountmgr.sys is safe when using a legitimate Windows installation from Microsoft.
Is mountmgr.sys a Virus or Malware?
The real mountmgr.sys is NOT a virus. Malware may masquerade with similar names; verify signature and location.
How to Tell if mountmgr.sys is Legitimate or Malware
- File Location: Must be in
C:\Windows\System32\drivers\mountmgr.sys or closely related system path. Any mountmgr.sys elsewhere is suspicious.
- Digital Signature: Right-click the file -> Properties -> Digital Signatures. Should show a Microsoft signature (e.g., 'Microsoft Windows').
- Resource and Behavior: Kernel drivers should not appear as user-space processes. Check System event logs for mount events at
C:\Windows\System32\winevt\Logs\System.evtx.
- Integrity Check: Run
sfc /scannow to verify system file integrity and replace any corrupted components.
Red Flags: If mountmgr.sys is missing from System32\drivers, has a non-Microsoft signature, or shows frequent mounting errors after updates, run a full system scan and verify Windows integrity.
Why Is mountmgr.sys Running on My PC?
mountmgr.sys runs as part of Windows Boot and during storage-related events to mount or dismount volumes and manage drive letters, ensuring storage devices are accessible safely and efficiently.
Reasons it's running:
- System Startup and Volume Initialization: During Windows startup, Mount Manager initializes volume mounting to make disks ready for use.
- Device Connection Events: Plugging in USB, external drives, or PCIe storage triggers mounting tasks.
- Drive Letter Management: Assigns and reassigns drive letters as disks are added or removed.
- Disk Reconfiguration: Handles re-scans, partition changes, and dynamic disk changes without user intervention.
- Mount Point and File System Coordination: Coordinates with file system drivers to ensure consistent access and safe detachments when needed.
Can I Disable or Remove mountmgr.sys?
No, you should not disable mountmgr.sys. It is a core Windows driver responsible for mounting and managing volumes; disabling can render disks unusable and destabilize the OS.
How to Stop mountmgr.sys
- Not Recommended: Avoid stopping core OS drivers. Disabling can cause system instability and data loss.
- Temporary Mitigation (Not Recommended): If absolutely necessary for troubleshooting, attempt to limit mounting by detaching external drives first.
- Stop from Command Line (Not Recommended): Open an elevated Command Prompt and run 'sc stop mountmgr' (may fail or cause instability).
- Safe Boot: Restart in Safe Mode to minimize mounted volumes during troubleshooting.
- Permanent Avoidance (Not Recommended): Do not attempt to uninstall or permanently disable; instead use safe maintenance and OS recovery options.
How to Remove Mount Manager Driver (Not Supported)
- ✔ This driver is an integral part of Windows; it cannot be uninstalled like a standard program.
- ✔ If you suspect corruption, use System File Checker (sfc /scannow) and DISM to repair Windows components.
- ✔ Consider a repair install or Windows in-place upgrade to restore system drivers and components.
- ✔ Back up data before attempting major OS repair.
- ✔ If you need to disable mounting behavior, use built-in policies and settings and revert after testing.
Common Problems: Volume Mounting and Mount Manager
Mount Manager issues typically involve volumes not mounting, drive letter conflicts, or unstable disk mounts after updates.
Common Causes & Solutions
- New disks or USB drives connected: Let Mount Manager initialize them; if not, try Disk Management (diskmgmt.msc) to manually mount or assign a letter.
- Drive letter conflicts: Open Disk Management (diskmgmt.msc) and reassign letters to conflicting drives; remove duplicates.
- Corrupted Mount Manager data: Run sfc /scannow and DISM to repair system files; check for Windows updates.
- Outdated storage driver stack: Update storage drivers and firmware from the device vendor; ensure Windows is up to date.
- USB or external device not recognized: Test on another port; unplug and replug; try a different USB cable; check Power Management settings.
- Disabling auto-mount in policy or registry: Restore default Mount Manager behavior by reversing policy changes and restarting.
Quick Fixes:
1. Open Disk Management (diskmgmt.msc) to identify unmounted disks and assign letters
2. Run sfc /scannow and DISM to repair system files
3. Update storage drivers and firmware
4. Disconnect external storage then reconnect to trigger mounting
5. Reboot to apply mounting changes
Frequently Asked Questions
What is mountmgr.sys?
mountmgr.sys is the Windows Mount Manager driver that coordinates mounting and dismounting of volumes and manages drive letters for storage devices.
Is mountmgr.sys safe?
Yes, it is a legitimate Windows kernel driver. Verify its location (C:\\Windows\\System32\\drivers\\mountmgr.sys) and signature from Microsoft.
Can I disable mountmgr.sys?
Disabling mountmgr.sys is not recommended; it can prevent disks from mounting and cause system instability.
Why does mountmgr.sys cause high disk I/O?
It may happen during initial mounting of multiple volumes, after hardware changes, or if a problematic USB device is connected.
How do I fix mountmgr.sys errors?
Run sfc /scannow, use DISM, check for updates, and verify the integrity of Windows system files. Consider a repair install if errors persist.
Where is mountmgr.sys located?
C:\\Windows\\System32\\drivers\\mountmgr.sys