Error: Syntax problem: directory (dictionary) with more than 4095 entries, Fixup failed! (0x0)

This error message means that the input file has a syntactical problem and therefore cannot be converted to PDF/A. One of the so-called implementation limits is not met. You can see the detailed information in the log file:

1. Open PDF Compressor 
2. Click on File → Options → Configuration
3. Under <Logfile> you will see the path where the log file will be written <C:\ProgramData\Foxit\PDF Compressor\>
4. Click on Show

Then you will see the error message:

Wed Apr 19 18:00:28 2023: 3: Warning: Job Name: Conversion to PDF/A-1B failed: Error: Syntax problem: directory (dictionary) with more than 4095 entries, Fixup failed! (0x0): <input path>

To make possible the conversion, it is necessary to rasterize the file to completely rebuild it. Normally this happens automatically and a 'fallback' variant is used to make possible the conversion to PDF/A. In other words, the file will be rasterized:

Wed Apr 19 18:00:28 2023: 3: Info: File Name <input path> could not be processed in the preferred mode, therefore the 'fallback' variant is used (605).

If for some reason the PDF Compressor doesn't change to the grid fallback, then activate manually this option:

1. Do a right-mouse on the job file
2. Click on Properties
3. Click on Input → Rasterize PDF Input → Always