Quicktime (v10.2) not exporting anymore.

It seems my non-pro version of QuickTime (v10.2) is no longer exporting files.

I often do 2 things:

1) export videos straight to facebook via Web export or something similar

2) trim and Save As videos

When doing so, I am shown the export dialog showing the progress and past exports etc.

In the last few weeks, both of these export functions result in nothing happening... no export dialog, no final export file, nothing at all. Quicktime just sits there doing nothing.

Any ideas?

(OS says all software updates have been made)

Do I reinstall Quicktime? How do I even do that? Any other options? Easy fix?