Summary

This guide helps you troubleshoot and resolve: How to troubleshoot and fix a document scanner that produces blurry, streaked, or cropped scans on Windows and macOS. Follow the steps below to fix the issue.

Common Causes

If your scanner is producing blurry, streaked, or cropped scans, the issue is usually caused by dirty glass, incorrect resolution settings, or outdated drivers. This guide walks you through the most common causes and fixes for both Windows and macOS, starting with the simplest solutions first.

Quick Fix Steps

Try these steps in order. Most scanner quality issues are resolved within the first three.

1. Clean the scanner glass and lid thoroughly.
2. Update or reinstall the scanner driver.
3. Adjust the scan resolution (DPI) to at least 300.
4. Check the document type and placement on the glass.
5. Calibrate the scanner using the manufacturer's software.

Detailed Instructions

Clean the Scanner Glass and Lid

Dust, fingerprints, and smudges are the most common cause of streaks and blurry scans. Even a thin film can distort the image.

1. Turn off the scanner and unplug it from power.
2. Open the scanner lid.
3. Spray a small amount of glass cleaner onto a soft, lint-free cloth (never spray directly onto the glass).
4. Wipe the scanner glass in slow, straight motions.
5. Wipe the underside of the lid, paying attention to the white calibration strip on flatbed scanners.
6. Dry with a clean microfibre cloth.
7. Close the lid and test the scanner.

Adjust Scan Resolution and Settings

Low resolution settings produce blurry or pixelated scans, especially for text and small images.

Windows

1. Open the Settings app and navigate to Bluetooth & devices > Scanners & printers.
2. Click your scanner and select Manage.
3. Choose Scanner properties or open your scanning app (such as Windows Scan or the manufacturer's software).
4. Set the resolution to 300 DPI for documents or 600 DPI for photos.
5. Select Colour or Greyscale as appropriate, and ensure Auto-crop is enabled if cropping is the issue.

macOS

1. Open Image Capture from /Applications/Image Capture.app or via Spotlight.
2. Select your scanner from the Devices list.
3. Click Show Details to expand the settings panel.
4. Set Resolution to 300 DPI for documents or 600 DPI for photos.
5. Adjust the Scan Size to match your document, or enable Detect Separate Items to fix cropping issues.
6. Click Scan to test.

Update or Reinstall the Scanner Driver

Outdated or corrupted drivers can cause misaligned scans, colour issues, and cropping errors.

Windows

1. Press Windows + X and select Device Manager.
2. Expand the Imaging devices category.
3. Right-click your scanner and select Update driver.
4. Choose Search automatically for drivers.
5. If the issue persists, right-click the scanner again and select Uninstall device, then restart your computer. Windows will attempt to reinstall the driver automatically.

macOS

1. Click the Apple menu and select System Settings.
2. Navigate to General > Software Update.
3. Install any available updates, as macOS includes built-in scanner driver updates.
4. If using a third-party scanner, visit the manufacturer's website and download the latest macOS driver or .pkg installer.
5. Restart your Mac after installation.

Check Document Placement and Type

Misaligned documents are a frequent cause of cropped or skewed scans.

• Place documents face-down on the glass, aligned with the corner markers (usually the top-left).
• For ADF scanners, ensure pages are loaded straight and not folded or stapled.
• Remove any sticky notes, paper clips, or tabs before scanning.
• If scanning thick books or magazines, lift the lid hinge slightly to allow even pressure across the page.

Calibrate the Scanner

Flatbed scanners should be calibrated periodically to maintain colour accuracy and alignment.

1. Open the manufacturer's scanning software (such as Epson Scan, Canon IJ Scan Utility, or HP Smart).
2. Look for a Calibrate or Maintenance option, usually under Settings or Tools.
3. Follow the on-screen prompts. You may be asked to scan a calibration sheet that came with your scanner.
4. Restart the scanner when complete.

Troubleshooting

Scans Still Have Streaks After Cleaning

If streaks remain after cleaning, the issue may be a scratched glass surface or a failing scanner lamp. Inspect the glass under bright light for scratches. If the glass is damaged or the lamp is dim, the scanner may require professional service or replacement. Contact our support team if you need assistance assessing the hardware.

Scans Are Cropped Incorrectly

Cropping issues often relate to the scan area settings or document size selection. In your scanning software, manually set the scan area to match the document size (such as A4 or Letter) rather than relying on auto-detect. If the issue only occurs with multi-page ADF scans, check that the page size is consistent throughout the batch.

Scanner Not Detected at All

If your computer does not recognise the scanner, check the USB or network connection. For network scanners, ensure the device is connected to the same network as your computer. You may also need to check our guide on hardware devices not responding.

Related Articles

• Printer not printing / offline
• Hardware device not responding
• How to update drivers on Windows
• How to update drivers on macOS
• How to connect Bluetooth devices

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