This is know issue
You can upgrade sepm 12.1.5 or you can find SEP client package on file connect.
Export of client package from SEPM never finishes
Fix ID: 2627397
Symptom: Export of a client package from SEPM does not complete on non-English Windows, when SEPM is configured to use the embedded database.
Solution: SEPM was modified to use a different database method to obtain binary stream data.
New fixes and features in Symantec Endpoint Protection 12.1 Release Update 1 Maintenance Pack 1
Edit
You can find Unmanaged SEP client package on Installation media.