Exporting STL on INVENTOR 2018 will not save modified assemblies

[Anonymous]

When I open an existing IAM I can export it to an STL but when I modify that same IAM and export it as an STL it allows me to do it but when I go to the file where I saved exported it to it is not there?  I tried this on multiple machines and I am getting the same issue?  It allows me to do it but it isn't actually exporting the file.  I tried exporting it to the desktop, it allows me to do that also but it is not on the desktop after doing so either?

Any help would be greatly appreciated

[JDMather]

@Anonymous

Your second video clearly shows issues with the combustion chamber.

In the image below I hid most of the parts - notice that most of the parts have a green check mark indicating that they passed Inventor Quality Check, while two of the parts show an i inside a circle indicating geometry issues.

[JDMather]

The parts could be repaired - but this process requires an advanced knowledge of Inventor.

[Anonymous]

In the past I would just create a simplified part then save it and open that part and manipulate it
Is it not possible to this in 2018?

[JDMather]

In your 2014 image you are in an assembly environment.

You did not post image of 2018 where it is not working - so I can't tell if you are in part environment or in assembly environment.