Unable to remap mouse buttons. This might be caused by a corrupted or missing "default.btnmenu" file, which is stored in the folder called "Buttons" within your WorkSpace in a path similar to the following
C:\ProgramData\Bentley\MicroStation V8i (SELECTseries)\WorkSpace\Interfaces\Buttons
(to check the path to your WorkSpace click on menu WorkSpace>About Wokspace)
If the file "default.btnmenu" is missing or is corrupted, you can try to:
Option 1
Replace it with the same "default.btnmenu" file from another installation of the same version of MicroStation that does not have any issues
Option 2
Remove the file "default.btnmenu" from the \WorkSpace\Interfaces\Buttons folder and run a Repair of the installation of MicroStation from the Control Panel (Programs and Features)
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Note:
You can also try to reset your upf file:
How To Reset User Preferences and Delete MicroStation‘s Temporary Files