Solution : https://service.sap.com/sap/support/notes/757093 (SAP Service marketplace login required)
Summary : 
      This SAP Note discusses important considerations and steps for performing a client copy in a CRM landscape. It emphasizes the necessity to follow specific CRM-related guidelines, manage data consistency across systems, and adjust logical system names via BDLS. Key notes for pre- and post-processing client copy tasks are highlighted, including Note 24853 which discusses client copy functionalities. Problems such as incorrect copying of Site IDs using certain profiles are also addressed, advising reference to Note 770783 for resolution. For any issues beyond this scope, opening an OSS message or consulting onsite is recommended.
Key words : 
relevant client copy documentation provided bythe basis team, client copy-related notes assigned, basis notes listed directly, easiest formaintaining data consistency, 24853  - client copy functionality552711 - faq, newly-created r3 backendmust, important crm-specific issues, copy application data, client copy tools, customer-specific requirements
Related Notes : 
       
| 770783 | Site IDs/Employees copied during customizing client copy | 
| 585725 | Incorrect system release determined for R/3 site | 
| 577778 | Postprocessing after client copy | 
| 552711 | FAQ: Client copy | 
| 550894 | CC-ADMIN: Setting up a new client | 
| 519488 | logsys corrections for enabling the 'BDLS' tx conversion | 
| 457707 | Change of the back-end system | 
| 418886 | Download: Products not found or not changeable | 
| 24853 | CC-INFO: Client copy, functionality | 
| 19574 | CC-ADMIN: Controlling data selection during client copy | 
| 2857 | What table delivery classes are there? What is their signifi |