Document Number: OSUP1008
Product: Observer 4.x
Date: 8-21-97
Title: Failed in OPEN_ADAPTER_4 error

Failed in OPEN_ADAPTER_4 error
The error “Failed in Open Adapter_4” then “Failed to Allocate VxD packet buffer” reflects two problems:
a) a driver setup for a non-existent adapter, and
b) an older version of Observer

The error comes from Observer trying to bind an adapter that does not exist in the system.

Versions of Observer 4.0 or greater gets around this by offering an adapter choice when it encounters a non-existent adapter, as opposed to giving up.

You can either update to the latest version, or if you would like to continue to use your current version of Observer, go into your Registry and delete the following key:
HKEY_LOCAL_MACHINE
 SOFTWARE
  Network Instruments
   Observer
     General
     Adapter

If you delete the "Adapter" key, Observer will ask you for an adapter next time you start the program, and you can select the "real" adapter.