Microsoft KB Archive/230768

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OLEXP: Mailto Link Does Not Work with % Character and 2 Letters

Article ID: 230768

Article Last Modified on 1/24/2007



APPLIES TO

  • Microsoft Outlook Express 5.0
  • Microsoft Outlook Express 4.01 Service Pack 1
  • Microsoft Outlook Express 4.01 Service Pack 2
  • Microsoft Outlook Express 4.0
  • Microsoft Outlook Express 5.0
  • Microsoft Outlook Express 4.01 Service Pack 1
  • Microsoft Outlook Express 4.01 Service Pack 2
  • Microsoft Outlook Express 5.0
  • Microsoft Outlook Express 4.01 Service Pack 1
  • Microsoft Outlook Express 4.01 Service Pack 2
  • Microsoft Outlook Express 4.0



This article was previously published under Q230768

For information about the differences between Microsoft Outlook Express and Microsoft Outlook e-mail clients, click the following article number to view the article in the Microsoft Knowledge Base:

257824 OL2000: Differences Between Outlook and Outlook Express


SYMPTOMS

Whenever an Outlook Express "mailto" link contains a percent character followed by 2 letter characters in the A-F or a-f range, for example %BB, the address information is not parsed correctly, damaging the address. Note that this occurs even though addresses of this type are considered to be Request For Comment (RFC) compliant.

CAUSE

This problem occurs because Outlook Express translates the percent character as an escape character. If the two characters following this percent sign are in the A-F range, they are converted to their corresponding hexadecimal values (A = 1010, B = 1011, etc) and then put together to form a single-byte value with the first character taking the upper four bits and the second taking the lower four bits. For example, %CA results in a value of 11001010.

WORKAROUND

To work around this problem, do not use a percent character followed by 2 letter characters in the A-F range in a mailto link.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.


Keywords: kbui kbprb KB230768