Missing Function RenderPageBitmapHighQuality

Updated:September 22, 2025

With the newly updated version of IronOCR 2025.4.4, we added a new internal method for our algroithm when converting to Bitmaps. However, users who updated from the older version might encounter this exception below.

System.InvalidOperationException: 'No function was found with the name RenderPageBitmapHighQuality with error code (127).'

The exception message states that the function is not within the internal API. The main issue stems from the fact the IronOcrInterop.dll was not updated to the latest version to match the version used in IronOCr 2025.4.4. Due to the version mismatch, the library isn't aware that the internal API has been updated and can't find the new RenderPageBitmapHighQuality function as it was still referencing the old set of API with the outdated IronOcrInterop.dll.

Solution

A quick solution is to delete the existing bin folder and rebuild the project again. Rebuilding the project would generate a newly updated IronOcrInterop.dll that matches the updated version, which resolves this issue. Afterwards, trying running your project again and the error should no longer persist.

Curtis Chau

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Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.