SAP Basis Tech Supports

Symptom
You require information about the side-effects of the “Unicode OFF” mode in SAP GUI for Windows.
Other terms
SAP GUI; Unicode; switch; SAPLogon; deactivation of Unicode
Reason and Prerequisites
You may have been asked to activate the “Unicode OFF” switch to correct a problem that has occurred in connection with a Unicode system. However, using this switch has certain risks, therefore, it should only be activated in emergencies. This note describes possible problems.
Solution
The following problems may occur when “Unicode OFF” is set and SAP GUI is used with a Unicode system:
Data may become corrupt when data that cannot be displayed with the front-end code page is saved again inadvertently (”#” is saved to the database).The display is restricted to one code page.
In general, we recommend that you use SAP GUI for Windows 6.40 or higher with Unicode systems because a large number of Unicode enhancements was implemented in this SAP GUI release.