With SAP S/4HANA 2020 FPS01 SAP has added feature in FI initial load. With classic way it was always you need to run the package of documents and do hit and trial but now it little easy.
I will not explain much in theory rather take you directly to SAP screens. See how
Please note to understand this problem and solution you need to have basic understanding of how Initial Load works and what it is all about in SAP Central Finance which you can read here end to end as a sequence of blogs.
CLICK HERE
Make below extraction settings
Extract the data as a part of normal process.
Then run the simulation of FI postings
Lets say i have a package KEY - DPRDCLNT002CD01202012345678901234567899 (example only)
Enter package key: DPRDCLNT002CD01202012345678901234567899 (example only, i have entered different in the SAP screenshot)
(please note when SAP runs the extraction of FI documents in it creates packages and bundle several documents in a package. Each package is represented by unique package key)
Now it gives us the clear detail per document - what is posted and what is not
Now you have clarity which document is failing which you can check in detail as below
Like in this example one document is in error and Internal Order is missing thats why the error generates which can be fixed.
With this feature the analysis of the FI load becomes easy as for COBK, AUFK and others we have choose in AIF to analyse individual document which is very easy but at least with this feature the work of project team can be made easy when the initial load is executed in test cycles or for production run.
Hope it helps you in your project...