Message type: E = Error
Message class:  CNV - Conversion: Messages for Conversion Services (CNCC) 
Message number: 052
Message text: Program start not possible at this point.
The start program found that it is not possible to start any additional
conversion programs at the moment. There may be several reasons for
that.
The maximum number of conversion processes as defined in the technical
settings for the conversion package is already running.
Currently, no background process that could be used by the conversion
program is available. (It is not possible to use processes of class A,
and one background process must be left free for technical reasons.)
The logical sequence relations within the package do not allow for other
conversion programs to be started at this point:
because not all programs with a given sequence number are finished yet.
because a direct predecessor relation does not allow for other programs
to be started now.
The technical sequence relations in the package do not allow for other
conversion programs to be started at this point:
because programs with pre-selection are still running
because end processing for a given table cannot be started until this
table has been converted
because the index for a given table cannot be re-created until
end-processing for this table is complete
Available system resources in the areas of CPU, I/O, main memory or
rollback requirements as defined for the given system are not sufficient
for starting another conversion job.
The programs or jobs that you want to start do not exist in the system
any more, or are not known to the conversion package.
Error message extract from SAP system. Copyright SAP SE.
The SAP error message "CNV052 Program start not possible at this point" typically occurs in the context of data migration or conversion processes, particularly when using SAP's tools for data migration, such as the SAP S/4HANA Migration Cockpit or other conversion programs.
Cause: Incorrect Program State: The program may be in a state where it cannot be executed. This could be due to a previous step not being completed successfully or the program being called at an inappropriate time in the migration process. Missing Prerequisites: Certain prerequisites or configurations may not have been met before attempting to start the program. Authorization Issues: The user may not have the necessary authorizations to execute the program. System Configuration: There may be issues with the system configuration or settings that prevent the program from starting.
Solution: Check Program Status: Ensure that all previous steps in the migration or conversion process have been completed successfully. Review logs for any errors that
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