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Japnease subject showing "?" mark when exporting eml to mbox

Hi team,
I am working on java I am using Aspose 18.6 jars. When I am converting eml to Mbox the subject is a mismatch and not showing proper subject. Please check the attachment.

JapneaseCharacter.zip (9.6 KB)


We have tried to convert EML to MBOX using Aspose.Email for Java 18.11 and it is converted successfully with no “?” marks found in subject. Please have a look at the generated MBOX file here inbox.zip (3.6 KB).

Moreover, it is requested to please try with latest version of our API and let us know if issue still exists.

Hi MuzammilKhan,
I have attached the two eml file one file is original file and another is exported file. So please check the attachment in the subject the exported eml file is showing “?” in between the subject.
And please check the attachment which you provided it is also showing the “?” between the subject.
Please check the attachment below. I have attached the screenshot and original eml file.

JapneaseCharacter.zip (242.5 KB)


We are sorry for inconvenience.
We are unable to find any “?” marks in any of the EML or generated MBOX file, please have a look at the screenshots EML_No_Marks.png (68.0 KB) and Converted_mbox.png (13.0 KB)

Moreover, it is requested to kindly share what platform are you using and which application is being used to view EML and MBOX files. So that we could investigate further.

Hi MuzammilKhan,
I think you open that file into windows.
Can you please check that mbox file into apple mail client on mac machine.


Thank you for your feedback.

We were able to reproduce this issue and it has been logged with ID “EMAILJAVA-34465” for further investigation. You will automatically be informed here once we have more information to share.


Please find the MBOX file here inbox_new.zip (6.7 KB) and check it. This is exported from “Original file.eml” using Aspose.Email for Java 18.11 and the following code sample is used.

        FileOutputStream writeStream = new FileOutputStream(dataDir + "inbox.mbox");
		try {
			MboxrdStorageWriter writer = new MboxrdStorageWriter(writeStream, false);
			try {
				MailMessage msg = MailMessage.load(dataDir + "Message.msg");
				String[] fromMarker = { null };
				writer.writeMessage(msg, fromMarker);
			} finally {
				if (writer != null)
					((IDisposable) writer).dispose();
		} finally {
			if (writeStream != null)

It is requested to test with Aspose.Email for Java 18.11 and share your feedback with us.