Why Is the Scanning Process Taking So Long?

Duplicate Detective performs a thorough hash-based scan of every file in your selected folders. This process is intentionally deep and comprehensive, which means it can take a significant amount of time for large folders.

Why Scanning Takes Time

To guarantee 100% accuracy, Duplicate Detective reads the contents of each file and generates a unique hash value. It then compares these hash values across all files to identify exact duplicates. This is the only reliable method for confirming that two files are truly identical, but it is computationally intensive, especially when dealing with thousands of files.

Scan duration is affected by:

• Number of files -- More files means more comparisons.
• File sizes -- Larger files take longer to hash.
• Storage speed -- Slower drives (such as traditional hard drives or network volumes) will increase scan time compared to a fast SSD.
• System performance -- Available CPU and memory resources on your Mac also play a role.

How to Reduce Scan Time

If a scan is taking longer than expected, consider the following approaches:

• Scan in batches. Instead of scanning an entire drive at once, select individual subfolders and scan them one at a time.
• Increase the minimum file size. In Settings, raise the minimum file size threshold to skip smaller files and reduce the total number of files being compared.
• Exclude unnecessary folders. Use the excluded folders list in Settings to skip directories you know do not contain duplicates.

The progress bar and status messages in the app will confirm that the scan is still running. If the scan is actively progressing, it is best to let it complete for the most accurate results.