Have you tried different import option when you open the step file
Sometimes the part geometry contains very bad data structure
To access import diagnostic, right click on imported feature in tree. You cannot add any features to tree for option to be available.
Can you Attach one of the *.sldprt files here that exhibits this behavior of no Import Diagnostics available via right click?
In Inventor - did you run Quality Check on each *.ipt file?
Have you set to translate the geometry, or to reference the geometry?
Sorry guys, I'm not able to share the file due to NDA issues.
John when you mention import options, I have never actually done an 'import' as such. I simply open a file from Solidworks. In this case I just opened the STP file. Is there another way of 'importing'?
What I have found is that many of the surfaces with errors will fix themselves if I suppress and then suppress them. If I then save it as a STEP214 file and reopen, it has many more errors.
Jacob,..Tools > Options > Import or... here is a link for help on import options..
..and, a forum link to a similar question..