Description
Here's another unhappy story that, fingers crossed, should have a happy ending. After installing Windows XP Service Pack 2, you may find that your printer, scanner, VPN or other hardware/software no longer works. You may get the following errors:
''Multipass: unable to communicate with device...''
''Print Job Failed: The print job failed to complete. Reason: Unable to communicate with device...'' [Note: the print job may have actually completed!]
''Server Busy: The action cannot be completed because the other program is busy...'' [You press Switch or Retry and the error reappears].
This problem can affect some Canon printers, Nikon scanners, VPNs (Virtual Private Networks) or any other software or hardware that uses loopback addresses. Microsoft explain the issue as follows 'This problem occurs if the program connects to a loopback address other than 127.0.0.1. Windows XP Service Pack 2 (SP2) prevents connections to all IP addresses that are in the loopback address range except for 127.0.0.1.'

In other words, the new security features of XP SP2 may stop various types of programs from running properly on your system if they are using a technique that Microsoft considers unsafe. This may block communication between Windows and your hardware - hence the 'unable to communicate' or 'device busy errors'.

The biggest give away that the problem is occurring is if the device or software works normally on other Windows systems (eg Windows 2000) or XP without SP2. If you upgraded to XP SP2 and are not experiencing the problems described above, it is unlikely that you need the patch. However, you may want to download it and keep it handy for a future date - the problem has certainly baffled many people. Keep in mind it can affect both hardware and software.