If you install Lotus Notes on a 64-bit OS (e.g. Windows 7) and wish to use the "IBM Lotus Notes Single Login" you noticed that you always will be prompted for an password, even though Notes Single Login is enabled in the Notes Client via File - Security - User Security. {readmorelink}[...]{/readmorelink}

 

Read more: 8.5.2 FP2 solved Notes Single Login on a 64-bit operating system