SAP Note 25398 - General information on error message AA394

Symptom:

In the depreciation key, you can choose that acquisitions should only be allowed in the acquisition year of the fixed asset.
This is absolutely necessary in various constellations of the depreciation calculation, for example, for an activity-related depreciation or different forms of special depreciation.
If, however, a subnumber is now created, and it is required that the depreciation start date of the main number be copied via the screen layout rule, error message AA394 then occurs during the initial access to this subnumber.

Additional key words

T090C-XNAZUG SAPMA01B

Solution
This should be the case, and it is justified that the check refers to the depreciation start date and not to the acquisition date for the above-mentioned reasons.
In this respect, the error message, the description in Customizing and the documentation for this constellation is misleading. This will correspondingly be changed.
If you can only actually allow acquisitions in the acquisition year for organizational reasons, you must not pass the depreciation start date from the main number to the subnumber.