Created attachment 36791 [details]
Office 97 file with custom properties

For Office 97 files, it allows you to add custom properties but does not allow you to delete all custom properties.

Attached code to remove all custom properties:

InputStream is = new FileInputStream(new File("C:\test\CustomProperties.doc"));
POIFSFileSystem poifs = new POIFSFileSystem(is);
is.close();

DirectoryEntry dir = poifs.getRoot();
HPSFPropertiesOnlyDocument dis = new HPSFPropertiesOnlyDocument(poifs);
DocumentSummaryInformation dsi = dis.getDocumentSummaryInformation();

//Remove all Custom Properties
dsi.setCustomProperties(new CustomProperties());

dsi.write(dir, DocumentSummaryInformation.DEFAULT_STREAM_NAME);
si.write(dir, SummaryInformation.DEFAULT_STREAM_NAME);

OutputStream out = new FileOutputStream("C:\test\CustomProperties_2.doc");
poifs.writeFilesystem(out);
out.close();

In version 3.15 it worked correctly.
I need this functionality before moving on to version 4.10