Opening a large assembly in Solid Edge saved in a previous version, the Preview mode does not shows any components, even after doing the 'Fit' command.
The workaround is to save the visualization to new version, following these steps:
1) Open the assembly in Solid Edge with the new version.
2) In Solid Edge setting Options -> General, turn off the "Store geometry in Assembly for preview".
3) Save the Assembly.
4) Turn on "Store geometry in Assembly for preview".
5) Save the assembly again.
6) Reopen the assembly and the Preview will now be available.