Solution : https://service.sap.com/sap/support/notes/425507 (SAP Service marketplace login required)
Key words : 
settings\<username>\local settings\application data\sap\sap gui\tracesfor windows vista/7, \users\<username>\appdata\local\sap\sap gui\traces, prerequisites error analysing solution sapshortcut trace file, sapshortcut edit popupplease click, sap gui 620 patch < 56, sap gui 620 patch >= 56, sap logon window                     1, sapshortcut trace file sapshlib, sapshortcut trace file sapshcut, sapgui trace files reason
Related Notes : 
       
| 1442303 | SAP GUI 7.20 - replacement of SAPWORKDIR | 
| 519852 | Working directory of SAP GUI for Windows | 
| 103019 | SAPshortcut: Program parameters | 
| 99054 | SAPshortcut - Collective note | 
| 40024 | Transferring customer files to sapserv# using ftp |