Resources Base
Table of contents



Does Dynamic Web TWAIN support all scanners?
Are all scanners in the source list available?
What are the most common issues when clients start to use my scan application?
What are the Resources files?

License and Purchase

What can I do when my trial license expires?
When is a license validated?
How do I set my Dynamic Web TWAIN license?
Invalid product key
The current product key does not match the domain
Your trial product key has expired
You have exceeded the number of OCR attempts allowed by the current license


How to install Dynamic Web TWAIN?
What if I am installing over a previous version of the Dynamic Web TWAIN?
Can I install Dynamsoft Service silently?
How to uninstall Dynamsoft Service?
How to customize the Dynamsoft Service installer?
What does Dynamsoft Service do?
How to change the certificate of the Dynamsoft Service?
How to set the configuration of the Dynamsoft Service?
How to restart the Dynamsoft Service?
How to exclude WIA sources in the source list?
Is it necessary to call Dynamsoft.DWT.Load manually?
Where can I get the WebTWAIN instance(s) ?
How can I customize the WebTWAIN instance(s) ?
How do you configure the scan?
How many images can be scanned?
How do you use Custom DataSource Data?
How do you use Capability Negotiation?
How do you use a custom capability?
How to select a scanner by its name?
How to scan only a selected region?
How to enable remote scan?
How is the upload done?
Is SSL supported?
Can I upload multiple images as one file?
Can I upload multiple images as separate files in one go?
Can I upload the file as a base64 string?
How to specify the images to upload?
Can I change the header of the HTTP form?
Can I change the fields of the HTTP form?
Can I change the default field name of the file?
Can I show my own upgrade progress bar?
How do I know whether the upload succeeded?
Can I limit the size of the uploaded file?
Can I upload a big file in segments?
What are all the APIs Dynamic Web TWAIN provides for HTTP upload?
How to reduce the size of a resulting file?
How can I customize a resulting TIFF file?
How to hide the progress bar?
How to display the thumbnail viewer?
How to show or hide the Image Editor?
Is the Image Editor compatible across all platforms?
How to customize the installation dialog?
Can I OCR multiple languages at the same time?
Can I OCR multiple zones at the same time?
What is a LicenseChecker?
Comparison between OCR Basic and OCR Pro
How to improve the OCR accuracy?
When shall I use PDF Rasterizer?
When is PDF Rasterizer effective?
How to automatically deskew an image?
How to insert images to a specified index?
How to detect and discard blank pages automatically?
How to change the location or to rename the ‘Resources’ folder with Dynamic Web TWAIN?
How to customize the display language of Dynamic Web TWAIN?
How to customize the image editor?

Distribution and Deployment

How to set the MIME type?
How to know ResourcesPath is wrong?
Does installation require administrator rights?
Why is the browser prompting me to install Dynamsoft Service repeatedly?

Troubleshooting for end-users

How to use TWACKER to check if your device is TWAIN Compliant?
Download virtual scanner for testing
What are the differences between TWAIN and WIA?
How to test if your scanner supports ICA scanning on Mac OS?
How to test if your device is SANE compliant?
How to test if your camera is DirectShow compliant?
How to test if your camera is MediaDevices compliant?
How to enable and collect verbose log?
How to read log?
How to get the log files generated by the TWAIN Data Source Manager?
How to create dump files?
WebSocket Connection Issue
‘Activating the WebTwain instance’ prompt doesn’t disappear
How to disable end-user manual authorization when accessing local hardware?
How to resolve if Dynamic Web TWAIN stops working on insecure websites in Chrome v94?

Error List

Error message - General failure
Error message - A connection with the server could not be established
Error message - HTTP request error
Error message - HTTP process error
Error message - Only 24-bit true color bmp and 8-bit gray-scaled image are supported for JPEG compression
Error message - XMLHttpRequest cannot load XXX
Error message - Source is connected to the maximum supported number of applications
Error message - Sequence error
Error message - Request header field dwt-md5 is not allowed by Access-Control-Allow-Headers in preflight response
Error message - The handle is in the wrong state for the requested operation
Error message - The connection with the server was terminated abnormally

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