NVIN Scanner Troubleshooting Guide
Follow these troubleshooting instructions to resolve camera capture, corner cropping, file compression, and PDF merging issues.
Camera Viewfinder Displays a Black Screen or Crashes
Underlying Cause: Camera permission was denied during first launch, or another camera app (or flashlight) is locking the camera hardware.
- Go to your phone's Settings > Apps > NVIN Scanner > Permissions > Camera and select 'Allow while using the app'.
- Close any background camera apps, video conferencing apps, or flashlights.
- Restart NVIN Scanner to re-initialize the camera subsystem.
Scanned Documents Appear Blurry, Smudged, or Unreadable
Underlying Cause: Camera lens has fingerprint smudges, insufficient ambient lighting, or shutter was pressed before focus locked.
- Wipe your phone's rear camera lens with a clean microfiber cloth.
- Ensure the paper is illuminated by indirect daylight or overhead room lighting.
- Tap the screen directly over the document text to force auto-focus lock before capturing.
Automatic Edge Crop Detects the Table Instead of the Paper
Underlying Cause: Insufficient contrast between the document paper and the surface beneath it (e.g., white paper on a light laminate table).
- Place the paper on a contrasting surface, such as a dark desk, notebook cover, or floor mat.
- Manually drag the four circular corner pins on the crop preview screen to adjust borders.
Generated PDF File Size Is Too Large to Email or Upload
Underlying Cause: Document was saved using the 'Original Color' filter at full sensor resolution.
- Select the 'Black & White' filter preset before saving. This converts the background to solid white and compresses text to a fraction of the size.
- If color is required, check that you did not scan at an unnecessary extreme zoom.
PDF Merge Fails with 'Corrupted File' or Memory Error
Underlying Cause: One of the selected source PDFs is damaged, or the phone does not have enough storage space to compile the combined output.
- Verify that you have at least 100MB of free internal storage.
- Open each source PDF individually in Readora or another viewer to identify if one of the files is corrupt.
- Merge documents in batches of 5–10 files if compiling an exceptionally large multi-hundred page volume.
If you encounter unexpected errors or need further technical assistance, contact our mobile software engineering team with your phone model and Android version:
Was this documentation guide helpful?
Your feedback helps our engineering team refine application documentation.