Asset incomplete

Dear Experts,

I have created as asset through PO and I have set goods receipt check for it. not that I want to do MIGO for that asset, I receive following error:

Asset 1100 111000000000-0 is incomplete, check the asset

Message no. AAPO184

Diagnosis

The 'Incomplete' indicator was set for asset 1100 111000000000-0 because required entries were not made.

System Response

In the standard system, the system rejects the posting of the asset and issues an error message.

However, this message can be configured and therefore can be changed to a warning. However, you should take note that in this case postings are also made, although an additional account assignment is missing.

Procedure

Proceed as follows:

• The following applies for existing assets: Start the report Incomplete Assets - Detail List (RAUNVA00) for the asset and complete the missing entries for the asset as needed. Then post the transaction again.
• The following applies for new assets: Choose the Master Data push button and complete the asset master data.

I did the RAUNVA00 and I saw that in asset master data useful life is missing. But the asset I have created is using dep key of declining balance and does not need useful life. Could you please help me how to solve this problem. Do I have to make field of useful life optional for this dep key? if so, how?

Regards,