To fix the Labshell Extension error that causes SUM3D to go down randomly:
This typically happens when installing an older installer in Windows 10/8 that do not support older SUM3D libraries.
- Find the _RegDeregistra_LabShellExt_xSUM zip file in the SUM directory.
- Copy it into x64 folder and extract the zip.
- Cut both Deregistra files and move them into the x64 folder.
- Right click and run both _deregistra files as admin, which will unregister the labshell extension.