How To Fix SY406 - Table changes not possible with format &

SAP Error Message - Details

• Message type: E = Error

• Message class: SY - ABAP/4 system messages

• Message number: 406

• Message text: Table changes not possible with format &

What causes this issue?

You entered "&V1&" as the display format.
However, you cannot change a displayed internal table when this format
is set.
You can only change tables with standard formatting.

System Response

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

How to fix this error?

To change the table contents, overwrite the current format with a
space. If the table lines are structures, the format is automatically
set to "E" (column display with formatting).

Error message extract from SAP system. Copyright SAP SE.