Please help - no dialog box when exporting files (.stp, .igs, .X_T)

[Lucascannon]

So this morning (Saturday) I get to work and open a session. A large assembly I have exported over a thousand parts from. I am attempting to export a part and BOOM, no dialog box appears to choose options or file path. I tried a few different parts and same thing. Someone was using my station but does not remember changing a setting or preference. Does anyone know how to fix this? Please help I have been looking for export setting but nothing is helping.
Also after selecting, File- -> export .XXX, the screen just flashes and the little "x" in the corner of the window grays out (picture attached) and I cannot close that part/file. I have to close my entire session to close the part.

 

[Rob_N]

My guess is the dialog is lost in space, have you tried to reset your layout?

File -> Preferences -> User interface, then under layout Reset window position