XCON: Asserts Problem When Downloading Messages

• Microsoft Exchange Server, versions 5.0 and 5.5

SYMPTOMS

When you compose a MAPI Double-byte Character Set (DBCS) message in Exchange Client, type some text in the message body, change the font to Arial (Western) at some point after several DBCS characters, and send the message through outbound Internet mail (IMAIL), the received message will be corrupted. The DBCS text that is reformatted as Western typically contains a number of invalid characters that will cause the problem of asserts when the message is downloaded.

The problem may also appear in outbound messages composed as text and HTML. Only messages composed as Rich Text Format (RTF) are not affected by this problem.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.0.

This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 5.0. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K

MORE INFORMATION

This problem is related to code-page translation for outbound HTML and text, especially in cases when the outbound code-page is DBCS. The problem is caused by Windows NT translation functions converting undefined characters from range 0x80 - 0x9F into invalid Unicode range0x80 - 0x9F, and then into control range 0x00 - 0x1F. Emitting of unexpected control characters may cause various unpredictable problems. Assert in the debug build is caused by an outbound carriage return (CR) without a following linefeed (LF).

All characters that would get mapped into control region 0x00 - 0x1F are replaced with a question mark. Characters mapped into undefined region 0x80 - 0x9F are left alone (due to a possibility of character set mislabeling).