To access the Viewer again, you only need to create a new shortcut on the desktop and enter the following parameters:
For RFEM 5.26:
"C:\Program Files\Dlubal\RFEM 5.26\RFEM64.exe" /Viewer
For RSTAB 8.26:
"C:\Program Files\Dlubal\RSTAB 8.26\RSTAB64.exe" /Viewer
The existing program link can also be copied and supplemented with the addition /Viewer.