The following solution explains how to update and asset as Inactive, using the CA Asset Portfolio Management Data Importer.
CA Asset Portfolio Management 14.x, 17.x
Create an import mapping with the following 2 fields:
1. any primary key field, like serial number or host name
2. map the value 1 for the Asset.Inactive field.
Note: To set the asset back to Active, change the 1 to 0.
<Please see attached file for image>src="/servlet/servlet.FileDownload?file=0150c000004AKSaAAO" alt="InactiveMapping.png" width="1065" height="392">