Number of unchanged records for infotype &1 : &2

What causes this issue?

You have already entered records for infotype &V1& in the current
client before running the conversion program. The figure behind the
message text shows the number of records for infotype &V1& that could
not be changed.

System Response

These records could not be changed because entries already exist in the
new fields.

How to fix this error?

In client &v3& check that the fields for all existing records for
infotype &V1& contain the correct data.

Error message extract from SAP system. Copyright SAP SE.