Common Issues with Auslogics Disk Defrag Pro and How to Fix Them

Auslogics Disk Defrag Pro remains a staple utility for Windows maintenance in 2026, yet even stable software encounters conflicts with modern system architectures like Windows 11's security layers. Errors typically stem from insufficient permissions, conflicting background services (like Volume Shadow Copy), or aggressive antivirus filters flagging the software's drivers. This guide troubleshoots the most persistent issues users face today, focusing on practical file system repairs and configuration adjustments to restore functionality.

Common Errors

• Scheduled Defrag Not Running: The automated task fails to trigger at the set time, often due to Windows Task Scheduler overriding the software's triggers.
• Error: "Files Skipped": The defragmentation process completes but leaves specific files (usually MFT or system logs) fragmented because they are locked by Windows.
• VSS Error / Shadow Copies Lost: Running a defrag deletes System Restore points or triggers Volume Shadow Copy Service errors (e.g., 0x80042306).
• "Free Space Not Found": The software halts because it cannot find enough contiguous blocks to move large files, even if the disk technically has available gigabytes.
• Access Denied / Blocked by Administrator: The application refuses to launch or specific drive operations are blocked, often flagged by security software as a "PUP" (Potentially Unwanted Program).

Fix 1: Resolving Scheduled Task Failures

In recent Windows updates, the native Task Scheduler often suppresses third-party triggers to save power. You must force the task to run with higher privileges.

1. Open the Auslogics interface and go to Settings > Scheduler to ensure the schedule is actually enabled.
2. Press Win + R, type taskschd.msc, and press Enter to open Windows Task Scheduler.
3. Navigate to Task Scheduler Library > Auslogics > Disk Defrag.
4. Right-click the task and select Properties.
5. Under the General tab, check "Run with highest privileges" and ensure "Configure for" is set to your current Windows version.
6. Go to the Conditions tab and uncheck "Stop if the computer switches to battery power" if you are on a laptop to prevent interruptions.

Fix 2: Handling Locked Files (Files Skipped)

Standard defragmentation cannot move files that Windows is currently using, such as the Master File Table (MFT) or the paging file. You must use the offline mode.

1. Open the main application window.
2. Click the Boot-time Defrag tab (sometimes labeled "Offline Defragmentation" in newer builds).
3. Select Run on next computer startup.
4. Restart your computer immediately.
5. The software will load a minimal interface before Windows boots completely, allowing it to defragment locked system files safely.

Fix 3: Preventing VSS/Restore Point Deletion

Aggressive defragmentation moves blocks of data that the Volume Shadow Copy Service (VSS) tracks for backups. If too many blocks move, VSS "panics" and deletes old snapshots to maintain consistency.

1. Go to Settings > Algorithms.
2. Look for a checkbox labeled "VSS-compatible mode" or "Minimize growth of VSS storage area."
3. Enable this option to prevent the software from moving file blocks that are heavily tracked by System Restore.
4. If the error persists, open Windows Services (services.msc), find Volume Shadow Copy, right-click it, and select Restart.

Fix 4: Fixing "Free Space Not Found" Errors

This error occurs when free space exists but is scattered in tiny fragments, making it impossible to write a consolidated large file. You need to consolidate the empty space first.

1. Select the target drive in the drive list.
2. Instead of clicking the main "Defrag" button, click the small arrow next to it.
3. Select Defrag & Optimize (or specifically Free Space Consolidation if available).
4. Allow the process to finish; this moves all files to the beginning of the disk, creating a large continuous block of empty space at the end.
5. Once complete, run a standard Defrag check to ensure file continuity.

Fix 5: Bypassing "Access Denied" Blocks

Security suites like Malwarebytes or Windows Defender may flag disk tools as "Potentially Unwanted Programs" due to their ability to modify low-level file structures.

1. Right-click the Auslogics shortcut and select Properties > Compatibility.
2. Check the box "Run this program as an administrator."
3. Open your antivirus dashboard and locate the Exclusions or Allow List.
4. Add the installation folder (usually C:Program Files (x86)AuslogicsDisk Defrag) to the exclusion list.
5. If the program refuses to install initially, temporarily disable "Real-time protection" in Windows Security, install the software, and then immediately re-enable protection.

Prevention Tips

• Weekly Consolidation: Run a "Free Space Consolidation" once a month to prevent the "Free Space Not Found" error from recurring.
• SSD Awareness: Never run a standard defrag on an SSD. Use the SSD Optimize feature (TRIM command) strictly, as standard defrag reduces SSD lifespan.
• Check Disk Health: Run chkdsk /f in Command Prompt periodically to fix file system errors that cause the defragmenter to hang.

When to Contact Support

If the software consistently crashes the entire operating system (BSOD) or if your valid license key returns an "Invalid Activation" error despite following official instructions, you should reach out to support. Prepare a screenshot of the specific error code and export your System Information (msinfo32) before submitting a ticket.