3598596 - SUM: Waiting for flag file 'UPGANA.FLAG' in directory 'Migration/SUM/abap/load/sync'

Using the Database Migration Option (DMO) of the Software Update Manager (SUM) the upgrade fails with below error in phase MAIN_POSTCLEAN/SUBMOD_EVALUATE/SYNC_UPGEVAL_WAIT due to missing flag file called "UPGANA.FLAG". The following error message can be seen in PHASE_SYNC_NEW.LOG or PHASE_SYNC_NEW.SAV:

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1 ETQ201 Entering upgrade-phase "MAIN_POSTCLEAN/SUBMOD_EVALUATE/SYNC_UPGEVAL_WAIT" ("20250401071612").
2 ETQ367 Connect variables are set for standard instance access: System-nr = 'XXX', GwService = 'XXX' Client = '000'.
1 ETQ200 Executing actual phase 'MAIN_POSTCLEAN/SUBMOD_EVALUATE/SYNC_UPGEVAL_WAIT'.
1 ETQ399 Phase arguments:
2 ETQ399 Arg[File]    = 'doc/analysis/UPGANA.XML'
2 ETQ399 Arg[Options] = 'UPGANA'
1 ETQ000 ==================================================
4WETQ399 Flag file '/Migration/SUM/abap/load/sync/UPGANA.FLAG' does not yet exist.
3 ETQ399 [20250401071612] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
3 ETQ399 [20250401071752] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
3 ETQ399 [20250401071932] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
3 ETQ399 [20250401072112] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
3 ETQ399 [20250401072252] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
3 ETQ399 [20250401072432] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
3 ETQ399 [20250401072612] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
3 ETQ399 [20250401072752] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
3 ETQ399 [20250401072933] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
3 ETQ399 [20250401073113] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
4WETQ399 Flag file '/Migration/SUM/abap/load/sync/UPGANA.FLAG' does not yet exist.
3 ETQ399 [20250401073253] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...
3 ETQ399 [20250401073433] Waiting for FLAG file 'UPGANA.FLAG' in '/Migration/SUM/abap/load/sync'...

* Here is an example, the error message may slightly vary

• Software Update Manager (SUM)
• Database Migration Option (DMO)

UPGANA.FLAG, SUM, DMO, MAIN_POSTCLEAN/SUBMOD_EVALUATE/SYNC_UPGEVAL_WAIT, migration, PHASE_SYNC_NEW, Waiting for FLAG file, hang, hanging, not moving, stuck, Software Update Manager, Database Migration Option (DMO) , KBA , BC-UPG-TLS-TLA , Upgrade tools for ABAP , BC-UPG-DTM-TLA , Downtime Minimization for ABAP , Problem