Posting not possible; new Asset Accounting is inconsistent

What causes this issue?

Your system is being switched to <LS>SAP Accounting powered by SAP HANA
</>. This means only the new Asset Accounting is available to you. You
have to migrate from the classic Asset Accounting to the new Asset
Accounting, or complete the migration of Asset Accounting. Only then is
it possible for you to post in Asset Accounting again.
The following applies to the Customizing switch:
In the client, the Customizing switch for new Asset Accounting (<AB>
PARALLEL_VAL</>) has the status <ZK>In Preparation</>.
Alternatively, in the client the Customizing switch for new Asset
Accounting (<AB>PARALLEL_VAL</>) has the status <LS>Active (Posting Not
Possible in Client)</>. It is <ZH>not</> possible to post in accordance
with the new logic in the local system. The check displays an error
during the import (for example, inconsistent data).

System Response

As long as the Customizing switch <ZH>does not</> yet have the status
<ZK>Active</>, it is possible that the configuration could be
inconsistent. Therefore the system <ZH>does not</> allow any postings.

How to fix this error?

First complete the Customizing settings for new Asset Accounting and
then activate the Customizing switch at client level (in Customizing for
<LS>Asset Accounting</> under <DS:SIMG.VV_T093BSN_PV02_DC>Activate New
Asset Accounting</>).
If your data is consistent, posting is possible. If you do have
inconsistent data, you can analyze it in Customizing for <LS>Asset
Accounting</> under <DS:SIMG.FAA_CHECK_ACTIVATION_DC>Check Prerequisites
for Activating Asset Accounting (New)</>.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.